356 relations: Absolute value, Absolute zero, Absorption band, Acta Crystallographica, Adsorption, Age of the Earth, Albert Einstein, Allotropes of oxygen, Allotropy, Alpha decay, Alpha particle, American Journal of Physics, Ancient Greek philosophy, Angular momentum, Annalen der Physik, Antihydrogen, Antimatter, Antiproton, Antonius van den Broek, Argon, Asymptotic giant branch, Atmosphere of Earth, Atom probe, Atomic electron transition, Atomic mass, Atomic nucleus, Atomic number, Atomic orbital, Atomic radius, Avogadro constant, Azimuthal quantum number, Barium, Baryogenesis, Beryllium, Beta decay, Beta particle, Bethe, Big Bang, Big Bang nucleosynthesis, Billiard ball, Binding energy, Bismuth, Bohr model, Boron, Bose–Einstein condensate, Botany, Brownian motion, Caesium, Carat (mass), Carbon, ..., Carbon dioxide, Carbon-12, Carbon-14, Cathode ray, Center of mass, CERN, Chalcogen, Chemical & Engineering News, Chemical bond, Chemical compound, Chemical element, Chemical property, Chemical reaction, Chemistry, Circular symmetry, Coordination number, Copper, Cosmic ray spallation, Coulomb barrier, Coulomb's law, Covalent bond, Crystal, Crystal structure, Crystallization, Dark matter, Democritus, Deuterium, Diamond, Diatomic molecule, Distance, Down quark, Earth, Effective nuclear charge, Electric charge, Electric current, Electric field, Electric potential, Electromagnetic spectrum, Electromagnetism, Electron, Electron capture, Electron configuration, Electron energy loss spectroscopy, Electron shell, Electronvolt, Electrostatics, Elementary particle, Ellipsoid, Endeavour (journal), Endothermic process, Energy level, Ernest Marsden, Ernest Rutherford, Erwin Schrödinger, Exchange interaction, Excited state, Exothermic reaction, Exotic atom, Exponential decay, Extended periodic table, Femtometre, Fermi level, Fermion, Ferromagnetism, Fine structure, Foundations of Physics, Francis William Aston, Frederick Soddy, Frequency, Gamma ray, Gas, Gas-discharge lamp, Gauge boson, Geneva, George Johnstone Stoney, Gilbert N. Lewis, Gluon, Goddard Space Flight Center, Graphite, Group theory, H2g2, Hadron, Half-life, Hans Geiger, Harvard University Press, Helium, Helium-3, Henry Moseley, History of quantum mechanics, History of subatomic physics, Hydrogen, Hydrogen atom, Hydron (chemistry), Hydrostatic equilibrium, Hyperpolarization (physics), Identical particles, Imperial College London, Inductively coupled plasma atomic emission spectroscopy, Inductively coupled plasma mass spectrometry, Infinite divisibility, Internal conversion, International Union of Pure and Applied Chemistry, Interstellar medium, Invariant mass, Ion, Ionic crystal, Ionization, Ionization energy, Iron, Irving Langmuir, Island of stability, Isotope, Isotopes of hydrogen, Isotopes of lanthanum, Isotopes of lead, Isotopes of lithium, Isotopes of nitrogen, Isotopes of tantalum, Isotopes of vanadium, J. J. Thomson, James Chadwick, Jean Baptiste Perrin, John Dalton, Journal of the American Chemical Society, Laser, Law of multiple proportions, Lead, Leucippus, Light, Liquid, Lise Meitner, List of nuclides, Lithium, Local Bubble, Local density of states, Long and short scales, Louis de Broglie, Magnetic field, Magnetic moment, Magnetic resonance imaging, Magnetism, Margaret Todd (doctor), Mass, Mass number, Mass spectrometry, Mass-to-charge ratio, Mass–energy equivalence, Matrix mechanics, Matter, Maxima and minima, Metal, Milky Way, Mole (unit), Molecular cloud, Molecule, Momentum, Monthly Notices of the Royal Astronomical Society, Muon, Names of large numbers, Nanometre, NASA, Nature (journal), Nebula, Negative number, Neon, Neptunium, Neutrino, Neutron, Neutron capture, Neutron–proton ratio, Nickel, Niels Bohr, Nitrogen, Nobel Foundation, Nobel Prize, Nobel Prize in Physics, Noble gas, Nomenclature of Organic Chemistry, Nuclear binding energy, Nuclear fission, Nuclear force, Nuclear fusion, Nuclear Physics (journal), Nuclear shell model, Nuclear transmutation, Nucleon, Nucleosynthesis, Nuclide, Observable universe, Oganesson, Optical microscope, Organic compound, Otto Hahn, Otto Robert Frisch, Outline of chemistry, Oxide, Oxygen, Ozone, Paramagnetism, Particle, Particle accelerator, Particle detector, Pauli exclusion principle, Periodic table, Periodic trends, Philosophical Magazine, Photoelectric effect, Photon, Physica Scripta, Physical Review, Physics Today, Picometre, Planck constant, Plasma (physics), Plum pudding model, Plutonium, Plutonium-244, Point (geometry), Position (vector), Positron, Potassium-40, Potential energy, Potential well, Pressure, Primordial nuclide, Principal quantum number, Proceedings of the National Academy of Sciences of the United States of America, Proceedings of the Royal Society, Promethium, Proportionality (mathematics), Proton, Pyrite, Quantum mechanics, Quantum state, Quantum tunnelling, Quark, R-process, Radioactive decay, Radiochemistry, Radiometric dating, Radionuclide, Radium, Recombination (cosmology), Review of Scientific Instruments, Robert Brown (botanist, born 1773), S-process, Salt, Scanning tunneling microscope, Schrödinger equation, Science (journal), Silicate, SLAC National Accelerator Laboratory, Sodium chloride, Solar System, Solid, Spectral line, Spectroscopy, Speed of light, Spin (physics), Spin polarization, Spin–orbit interaction, Spontaneous emission, Stable isotope ratio, Stable nuclide, Standard Model, Standing wave, Star, Stark effect, Stationary state, Statistical physics, Stellar nucleosynthesis, Stern–Gerlach experiment, Stimulated emission, Strong interaction, Subatomic particle, Supernova, Synchrotron radiation, Technetium, Temperature, Thermal equilibrium, Timeline of atomic and subatomic physics, Tin, Tin oxide, Tin(II) oxide, Tin(IV) Oxide, Transactinide element, Transmission electron microscopy, Transuranium element, Triple-alpha process, Tritium, Uncertainty principle, Unified atomic mass unit, University of Toronto, Up quark, Uranium, Valence electron, Vector model of the atom, Water, Wave–particle duality, Waveform, Wavelength, Weak interaction, Werner Heisenberg, Whole number rule, Xenon, Zeeman effect. Expand index (306 more) » « Shrink index
In mathematics, the absolute value or modulus of a real number is the non-negative value of without regard to its sign.
Absolute zero is the lower limit of the thermodynamic temperature scale, a state at which the enthalpy and entropy of a cooled ideal gas reach their minimum value, taken as 0.
According to quantum mechanics, atoms and molecules can only hold certain defined quantities of energy, or exist in specific states.
Acta Crystallographica is a series of peer-reviewed scientific journals, with articles centred on crystallography, published by the International Union of Crystallography (IUCr).
Adsorption is the adhesion of atoms, ions or molecules from a gas, liquid or dissolved solid to a surface.
The age of the Earth is 4.54 ± 0.05 billion years This age may represent the age of the Earth’s accretion, of core formation, or of the material from which the Earth formed.
Albert Einstein (14 March 1879 – 18 April 1955) was a German-born theoretical physicist who developed the theory of relativity, one of the two pillars of modern physics (alongside quantum mechanics).
There are several known allotropes of oxygen.
Allotropy or allotropism is the property of some chemical elements to exist in two or more different forms, in the same physical state, known as allotropes of these elements.
Alpha decay or α-decay is a type of radioactive decay in which an atomic nucleus emits an alpha particle (helium nucleus) and thereby transforms or 'decays' into an atom with a mass number that is reduced by four and an atomic number that is reduced by two.
Alpha particles consist of two protons and two neutrons bound together into a particle identical to a helium-4 nucleus.
The American Journal of Physics is a monthly, peer-reviewed scientific journal published by the American Association of Physics Teachers and the American Institute of Physics.
Ancient Greek philosophy arose in the 6th century BC and continued throughout the Hellenistic period and the period in which Ancient Greece was part of the Roman Empire.
In physics, angular momentum (rarely, moment of momentum or rotational momentum) is the rotational equivalent of linear momentum.
Annalen der Physik (English: Annals of Physics) is one of the oldest scientific journals on physics and has been published since 1799.
Antihydrogen is the antimatter counterpart of hydrogen.
In modern physics, antimatter is defined as a material composed of the antiparticle (or "partners") to the corresponding particles of ordinary matter.
The antiproton,, (pronounced p-bar) is the antiparticle of the proton.
Antonius Johannes van den Broek (4 May 1870, Zoetermeer – 25 October 1926, Bilthoven) was a Dutch amateur physicist notable for being the first who realized that the number of an element in the periodic table (now called atomic number) corresponds to the charge of its atomic nucleus.
Argon is a chemical element with symbol Ar and atomic number 18.
The asymptotic giant branch (AGB) is a region of the Hertzsprung–Russell diagram populated by evolved cool luminous stars.
The atmosphere of Earth is the layer of gases, commonly known as air, that surrounds the planet Earth and is retained by Earth's gravity.
The atom probe was introduced at the by Erwin Wilhelm Müller and J. A. Panitz.
Atomic electron transition is a change of an electron from one energy level to another within an atom or artificial atom.
The atomic mass (ma) is the mass of an atom.
The atomic nucleus is the small, dense region consisting of protons and neutrons at the center of an atom, discovered in 1911 by Ernest Rutherford based on the 1909 Geiger–Marsden gold foil experiment.
The atomic number or proton number (symbol Z) of a chemical element is the number of protons found in the nucleus of an atom.
In quantum mechanics, an atomic orbital is a mathematical function that describes the wave-like behavior of either one electron or a pair of electrons in an atom.
The atomic radius of a chemical element is a measure of the size of its atoms, usually the mean or typical distance from the center of the nucleus to the boundary of the surrounding cloud of electrons.
In chemistry and physics, the Avogadro constant (named after scientist Amedeo Avogadro) is the number of constituent particles, usually atoms or molecules, that are contained in the amount of substance given by one mole.
The azimuthal quantum number is a quantum number for an atomic orbital that determines its orbital angular momentum and describes the shape of the orbital.
Barium is a chemical element with symbol Ba and atomic number 56.
In physical cosmology, baryogenesis is the hypothetical physical process that took place during the early universe that produced baryonic asymmetry, i.e. the imbalance of matter (baryons) and antimatter (antibaryons) in the observed universe.
Beryllium is a chemical element with symbol Be and atomic number 4.
In nuclear physics, beta decay (β-decay) is a type of radioactive decay in which a beta ray (fast energetic electron or positron) and a neutrino are emitted from an atomic nucleus.
A beta particle, also called beta ray or beta radiation, (symbol β) is a high-energy, high-speed electron or positron emitted by the radioactive decay of an atomic nucleus during the process of beta decay.
Bethe may refer to:;People.
The Big Bang theory is the prevailing cosmological model for the universe from the earliest known periods through its subsequent large-scale evolution.
In physical cosmology, Big Bang nucleosynthesis (abbreviated BBN, also known as primordial nucleosynthesis, arch(a)eonucleosynthesis, archonucleosynthesis, protonucleosynthesis and pal(a)eonucleosynthesis) refers to the production of nuclei other than those of the lightest isotope of hydrogen (hydrogen-1, 1H, having a single proton as a nucleus) during the early phases of the Universe.
A billiard ball is a small, hard ball used in cue sports, such as carom billiards, pool, and snooker.
Binding energy (also called separation energy) is the minimum energy required to disassemble a system of particles into separate parts.
Bismuth is a chemical element with symbol Bi and atomic number 83.
In atomic physics, the Rutherford–Bohr model or Bohr model or Bohr diagram, introduced by Niels Bohr and Ernest Rutherford in 1913, depicts the atom as a small, positively charged nucleus surrounded by electrons that travel in circular orbits around the nucleus—similar to the structure of the Solar System, but with attraction provided by electrostatic forces rather than gravity.
Boron is a chemical element with symbol B and atomic number 5.
A Bose–Einstein condensate (BEC) is a state of matter of a dilute gas of bosons cooled to temperatures very close to absolute zero.
Botany, also called plant science(s), plant biology or phytology, is the science of plant life and a branch of biology.
Brownian motion or pedesis (from πήδησις "leaping") is the random motion of particles suspended in a fluid (a liquid or a gas) resulting from their collision with the fast-moving molecules in the fluid.
Caesium (British spelling and IUPAC spelling) or cesium (American spelling) is a chemical element with symbol Cs and atomic number 55.
The carat (ct) (not to be confused with the karat, sometimes spelled carat, a unit of purity of gold alloys), is a unit of mass equal to 200 mg (0.2 g; 0.007055 oz) and is used for measuring gemstones and pearls.
Carbon (from carbo "coal") is a chemical element with symbol C and atomic number 6.
Carbon dioxide (chemical formula) is a colorless gas with a density about 60% higher than that of dry air.
Carbon-12 is the more abundant of the two stable isotopes of carbon (Carbon-13 being the other), amounting to 98.93% of the element carbon; its abundance is due to the triple-alpha process by which it is created in stars.
Carbon-14, 14C, or radiocarbon, is a radioactive isotope of carbon with an atomic nucleus containing 6 protons and 8 neutrons.
Cathode rays (also called an electron beam or e-beam) are streams of electrons observed in vacuum tubes.
In physics, the center of mass of a distribution of mass in space is the unique point where the weighted relative position of the distributed mass sums to zero, or the point where if a force is applied it moves in the direction of the force without rotating.
The European Organization for Nuclear Research (Organisation européenne pour la recherche nucléaire), known as CERN (derived from the name Conseil européen pour la recherche nucléaire), is a European research organization that operates the largest particle physics laboratory in the world.
The chalcogens are the chemical elements in group 16 of the periodic table.
Chemical & Engineering News (C&EN) is a weekly trade magazine published by the American Chemical Society, providing professional and technical information in the fields of chemistry and chemical engineering.
A chemical bond is a lasting attraction between atoms, ions or molecules that enables the formation of chemical compounds.
A chemical compound is a chemical substance composed of many identical molecules (or molecular entities) composed of atoms from more than one element held together by chemical bonds.
A chemical element is a species of atoms having the same number of protons in their atomic nuclei (that is, the same atomic number, or Z).
A chemical property is any of a material's properties that becomes evident during, or after, a chemical reaction; that is, any quality that can be established only by changing a substance's chemical identity.
A chemical reaction is a process that leads to the transformation of one set of chemical substances to another.
Chemistry is the scientific discipline involved with compounds composed of atoms, i.e. elements, and molecules, i.e. combinations of atoms: their composition, structure, properties, behavior and the changes they undergo during a reaction with other compounds.
In geometry, circular symmetry is a type of continuous symmetry for a planar object that can be rotated by any arbitrary angle and map onto itself.
In chemistry, crystallography, and materials science the coordination number, also called ligancy, of a central atom in a molecule or crystal is the number of atoms, molecules or ions bonded to it.
Copper is a chemical element with symbol Cu (from cuprum) and atomic number 29.
Cosmic ray spallation is a naturally occurring nuclear reaction causing nucleosynthesis.
The Coulomb barrier, named after Coulomb's law, which is in turn named after physicist Charles-Augustin de Coulomb, is the energy barrier due to electrostatic interaction that two nuclei need to overcome so they can get close enough to undergo a nuclear reaction.
Coulomb's law, or Coulomb's inverse-square law, is a law of physics for quantifying the amount of force with which stationary electrically charged particles repel or attract each other.
A covalent bond, also called a molecular bond, is a chemical bond that involves the sharing of electron pairs between atoms.
A crystal or crystalline solid is a solid material whose constituents (such as atoms, molecules, or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions.
In crystallography, crystal structure is a description of the ordered arrangement of atoms, ions or molecules in a crystalline material.
Crystallization is the (natural or artificial) process by which a solid forms, where the atoms or molecules are highly organized into a structure known as a crystal.
Dark matter is a theorized form of matter that is thought to account for approximately 80% of the matter in the universe, and about a quarter of its total energy density.
Democritus (Δημόκριτος, Dēmókritos, meaning "chosen of the people") was an Ancient Greek pre-Socratic philosopher primarily remembered today for his formulation of an atomic theory of the universe.
Deuterium (or hydrogen-2, symbol or, also known as heavy hydrogen) is one of two stable isotopes of hydrogen (the other being protium, or hydrogen-1).
Diamond is a solid form of carbon with a diamond cubic crystal structure.
Diatomic molecules are molecules composed of only two atoms, of the same or different chemical elements.
Distance is a numerical measurement of how far apart objects are.
The down quark or d quark (symbol: d) is the second-lightest of all quarks, a type of elementary particle, and a major constituent of matter.
Earth is the third planet from the Sun and the only astronomical object known to harbor life.
The effective nuclear charge (often symbolized as Z_ or Z^\ast) is the net positive charge experienced by an electron in a polyelectronic atom.
Electric charge is the physical property of matter that causes it to experience a force when placed in an electromagnetic field.
An electric current is a flow of electric charge.
An electric field is a vector field surrounding an electric charge that exerts force on other charges, attracting or repelling them.
An electric potential (also called the electric field potential, potential drop or the electrostatic potential) is the amount of work needed to move a unit positive charge from a reference point to a specific point inside the field without producing any acceleration.
The electromagnetic spectrum is the range of frequencies (the spectrum) of electromagnetic radiation and their respective wavelengths and photon energies.
Electromagnetism is a branch of physics involving the study of the electromagnetic force, a type of physical interaction that occurs between electrically charged particles.
The electron is a subatomic particle, symbol or, whose electric charge is negative one elementary charge.
Electron capture (K-electron capture, also K-capture, or L-electron capture, L-capture) is a process in which the proton-rich nucleus of an electrically neutral atom absorbs an inner atomic electron, usually from the K or L electron shell.
In atomic physics and quantum chemistry, the electron configuration is the distribution of electrons of an atom or molecule (or other physical structure) in atomic or molecular orbitals.
In electron energy loss spectroscopy (EELS) a material is exposed to a beam of electrons with a known, narrow range of kinetic energies.
In chemistry and atomic physics, an electron shell, or a principal energy level, may be thought of as an orbit followed by electrons around an atom's nucleus.
In physics, the electronvolt (symbol eV, also written electron-volt and electron volt) is a unit of energy equal to approximately joules (symbol J).
Electrostatics is a branch of physics that studies electric charges at rest.
In particle physics, an elementary particle or fundamental particle is a particle with no substructure, thus not composed of other particles.
An ellipsoid is a surface that may be obtained from a sphere by deforming it by means of directional scalings, or more generally, of an affine transformation.
Endeavour is a quarterly peer-reviewed academic journal published by Elsevier.
The term endothermic process describes the process or reaction in which the system absorbs energy from its surroundings, usually in the form of heat.
A quantum mechanical system or particle that is bound—that is, confined spatially—can only take on certain discrete values of energy.
Sir Ernest Marsden (19 February 1889 – 15 December 1970) was an English-New Zealand physicist.
Ernest Rutherford, 1st Baron Rutherford of Nelson, HFRSE LLD (30 August 1871 – 19 October 1937) was a New Zealand-born British physicist who came to be known as the father of nuclear physics.
Erwin Rudolf Josef Alexander Schrödinger (12 August 1887 – 4 January 1961), sometimes written as or, was a Nobel Prize-winning Austrian physicist who developed a number of fundamental results in the field of quantum theory, which formed the basis of wave mechanics: he formulated the wave equation (stationary and time-dependent Schrödinger equation) and revealed the identity of his development of the formalism and matrix mechanics.
In physics, the exchange interaction (with an exchange energy, and exchange term) is a quantum mechanical effect that only occurs between identical particles.
In quantum mechanics, an excited state of a system (such as an atom, molecule or nucleus) is any quantum state of the system that has a higher energy than the ground state (that is, more energy than the absolute minimum).
An exothermic reaction is a chemical reaction that releases energy by light or heat.
An exotic atom is an otherwise normal atom in which one or more sub-atomic particles have been replaced by other particles of the same charge.
A quantity is subject to exponential decay if it decreases at a rate proportional to its current value.
An extended periodic table theorizes about elements beyond oganesson (beyond period 7, or row 7).
The femtometre (American spelling femtometer, symbol fm derived from the Danish and Norwegian word femten, "fifteen"+Ancient Greek: μέτρον, metrοn, "unit of measurement") is an SI unit of length equal to 10−15 metres, which means a quadrillionth of one.
The Fermi level chemical potential for electrons (or electrochemical potential for electrons), usually denoted by µ or EF, of a body is a thermodynamic quantity, whose significance is the thermodynamic work required to add one electron to the body (not counting the work required to remove the electron from wherever it came from).
In particle physics, a fermion is a particle that follows Fermi–Dirac statistics.
Ferromagnetism is the basic mechanism by which certain materials (such as iron) form permanent magnets, or are attracted to magnets.
In atomic physics, the fine structure describes the splitting of the spectral lines of atoms due to electron spin and relativistic corrections to the non-relativistic Schrödinger equation.
Foundations of Physics is a monthly journal "devoted to the conceptual bases and fundamental theories of modern physics and cosmology, emphasizing the logical, methodological, and philosophical premises of modern physical theories and procedures".
Francis William Aston FRS (1 September 1877 – 20 November 1945) was an English chemist and physicist who won the 1922 Nobel Prize in Chemistry for his discovery, by means of his mass spectrograph, of isotopes, in a large number of non-radioactive elements, and for his enunciation of the whole number rule.
Frederick Soddy FRS (2 September 1877 – 22 September 1956) was an English radiochemist who explained, with Ernest Rutherford, that radioactivity is due to the transmutation of elements, now known to involve nuclear reactions.
Frequency is the number of occurrences of a repeating event per unit of time.
A gamma ray or gamma radiation (symbol γ or \gamma), is penetrating electromagnetic radiation arising from the radioactive decay of atomic nuclei.
Gas is one of the four fundamental states of matter (the others being solid, liquid, and plasma).
Gas-discharge lamps are a family of artificial light sources that generate light by sending an electric discharge through an ionized gas, a plasma.
In particle physics, a gauge boson is a force carrier, a bosonic particle that carries any of the fundamental interactions of nature, commonly called forces.
Geneva (Genève, Genèva, Genf, Ginevra, Genevra) is the second-most populous city in Switzerland (after Zürich) and the most populous city of the Romandy, the French-speaking part of Switzerland.
George Johnstone Stoney FRS (15 February 1826 – 5 July 1911) was an Irish physicist.
Gilbert Newton Lewis (October 25 (or 23), 1875 – March 23, 1946) was an American physical chemist known for the discovery of the covalent bond and his concept of electron pairs; his Lewis dot structures and other contributions to valence bond theory have shaped modern theories of chemical bonding.
A gluon is an elementary particle that acts as the exchange particle (or gauge boson) for the strong force between quarks.
The Goddard Space Flight Center (GSFC) is a major NASA space research laboratory located approximately northeast of Washington, D.C. in Greenbelt, Maryland, United States.
Graphite, archaically referred to as plumbago, is a crystalline allotrope of carbon, a semimetal, a native element mineral, and a form of coal.
In mathematics and abstract algebra, group theory studies the algebraic structures known as groups.
The h2g2 website is a British-based collaborative online encyclopedia project.
In particle physics, a hadron (ἁδρός, hadrós, "stout, thick") is a composite particle made of quarks held together by the strong force in a similar way as molecules are held together by the electromagnetic force.
Half-life (symbol t1⁄2) is the time required for a quantity to reduce to half its initial value.
Johannes Wilhelm "Hans" Geiger (30 September 1882 – 24 September 1945) was a German physicist.
Harvard University Press (HUP) is a publishing house established on January 13, 1913, as a division of Harvard University, and focused on academic publishing.
Helium (from lit) is a chemical element with symbol He and atomic number 2.
Helium-3 (He-3, also written as 3He, see also helion) is a light, non-radioactive isotope of helium with two protons and one neutron (common helium having two protons and two neutrons).
Henry Gwyn Jeffreys Moseley (23 November 1887 – 10 August 1915) was an English physicist, whose contribution to the science of physics was the justification from physical laws of the previous empirical and chemical concept of the atomic number.
The history of quantum mechanics is a fundamental part of the history of modern physics.
The idea that matter consists of smaller particles and that there exists a limited number of sorts of primary, smallest particles in nature has existed in natural philosophy at least since the 6th century BC.
Hydrogen is a chemical element with symbol H and atomic number 1.
A hydrogen atom is an atom of the chemical element hydrogen.
In chemistry, a hydron is the general name for a cationic form of atomic hydrogen, represented with the symbol.
In fluid mechanics, a fluid is said to be in hydrostatic equilibrium or hydrostatic balance when it is at rest, or when the flow velocity at each point is constant over time.
Hyperpolarization is the nuclear spin polarization of a material far beyond thermal equilibrium conditions.
Identical particles, also called indistinguishable or indiscernible particles, are particles that cannot be distinguished from one another, even in principle.
Imperial College London (officially Imperial College of Science, Technology and Medicine) is a public research university located in London, United Kingdom.
Inductively coupled plasma atomic emission spectroscopy (ICP-AES), also referred to as inductively coupled plasma optical emission spectrometry (ICP-OES), is an analytical technique used for the detection of chemical elements.
Inductively coupled plasma mass spectrometry (ICP-MS) is a type of mass spectrometry which is capable of detecting metals and several non-metals at concentrations as low as one part in 1015 (part per quadrillion, ppq) on non-interfered low-background isotopes.
Infinite divisibility arises in different ways in philosophy, physics, economics, order theory (a branch of mathematics), and probability theory (also a branch of mathematics).
Internal conversion is a radioactive decay process wherein an excited nucleus interacts electromagnetically with one of the orbital electrons of the atom.
The International Union of Pure and Applied Chemistry (IUPAC) is an international federation of National Adhering Organizations that represents chemists in individual countries.
In astronomy, the interstellar medium (ISM) is the matter and radiation that exists in the space between the star systems in a galaxy.
The invariant mass, rest mass, intrinsic mass, proper mass, or in the case of bound systems simply mass, is the portion of the total mass of an object or system of objects that is independent of the overall motion of the system.
An ion is an atom or molecule that has a non-zero net electrical charge (its total number of electrons is not equal to its total number of protons).
An ionic crystal is a crystal consisting of ions bound together by their electrostatic attraction.
Ionization or ionisation, is the process by which an atom or a molecule acquires a negative or positive charge by gaining or losing electrons to form ions, often in conjunction with other chemical changes.
The ionization energy (Ei) is qualitatively defined as the amount of energy required to remove the most loosely bound electron, the valence electron, of an isolated gaseous atom to form a cation.
Iron is a chemical element with symbol Fe (from ferrum) and atomic number 26.
Irving Langmuir (January 31, 1881 – August 16, 1957) was an American chemist and physicist.
In nuclear physics, the island of stability is the prediction that a set of heavy nuclides with a near magic number of protons and neutrons will temporarily reverse the trend of decreasing stability in elements heavier than uranium.
Isotopes are variants of a particular chemical element which differ in neutron number.
Hydrogen (1H) has three naturally occurring isotopes, sometimes denoted 1H, 2H, and 3H.
Naturally occurring lanthanum (57La) is composed of one stable (139La) and one radioactive (138La) isotope, with the stable isotope, 139La, being the most abundant (99.91% natural abundance).
Lead (82Pb) has four stable isotopes: 204Pb, 206Pb, 207Pb, 208Pb.
Naturally occurring lithium (3Li) is composed of two stable isotopes, lithium-6 and lithium-7, with the latter being far more abundant: about 92.5 percent of the atoms.
Natural nitrogen (7N) consists of two stable isotopes, nitrogen-14, which makes up the vast majority of naturally occurring nitrogen, and nitrogen-15, which is less common.
Natural tantalum (73Ta) consists of two stable isotopes: 181Ta (99.988%) and (0.012%).
Naturally occurring vanadium (23V) is composed of one stable isotope 51V and one radioactive isotope 50V with a half-life of 1.5×1017 years.
Sir Joseph John Thomson (18 December 1856 – 30 August 1940) was an English physicist and Nobel Laureate in Physics, credited with the discovery and identification of the electron; and with the discovery of the first subatomic particle.
Sir James Chadwick, (20 October 1891 – 24 July 1974) was an English physicist who was awarded the 1935 Nobel Prize in Physics for his discovery of the neutron in 1932.
Jean Baptiste Perrin (30 September 1870 – 17 April 1942) was a French physicist who, in his studies of the Brownian motion of minute particles suspended in liquids, verified Albert Einstein’s explanation of this phenomenon and thereby confirmed the atomic nature of matter (sedimentation equilibrium).
John Dalton FRS (6 September 1766 – 27 July 1844) was an English chemist, physicist, and meteorologist.
The Journal of the American Chemical Society (also known as JACS) is a weekly peer-reviewed scientific journal that was established in 1879 by the American Chemical Society.
A laser is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation.
In chemistry, the law of multiple proportions is one of the basic laws of stoichiometry used to establish the atomic theory, alongside the law of conservation of mass (matter) and the law of definite proportions.
Lead is a chemical element with symbol Pb (from the Latin plumbum) and atomic number 82.
Leucippus (Λεύκιππος, Leúkippos; fl. 5th cent. BCE) is reported in some ancient sources to have been a philosopher who was the earliest Greek to develop the theory of atomism—the idea that everything is composed entirely of various imperishable, indivisible elements called atoms.
Light is electromagnetic radiation within a certain portion of the electromagnetic spectrum.
A liquid is a nearly incompressible fluid that conforms to the shape of its container but retains a (nearly) constant volume independent of pressure.
Lise Meitner (7 November 1878 – 27 October 1968) was an Austrian-Swedish physicist who worked on radioactivity and nuclear physics.
This list of nuclides shows observed nuclides that either are stable or, if radioactive, have half-lives longer than one hour.
Lithium (from lit) is a chemical element with symbol Li and atomic number 3.
The Local Bubble, or Local Cavity, is a relative cavity in the interstellar medium (ISM) in the Orion Arm of the Milky Way.
Local density of states (LDOS) is a physical quantity that describes the density of states, but space-resolved.
The long and short scales are two of several large-number naming systems for integer powers of ten that use the same words with different meanings.
Louis Victor Pierre Raymond de Broglie, duke de Broglie (or; 15 August 1892 – 19 March 1987) was a French physicist who made groundbreaking contributions to quantum theory.
A magnetic field is a vector field that describes the magnetic influence of electrical currents and magnetized materials.
The magnetic moment is a quantity that represents the magnetic strength and orientation of a magnet or other object that produces a magnetic field.
Magnetic resonance imaging (MRI) is a medical imaging technique used in radiology to form pictures of the anatomy and the physiological processes of the body in both health and disease.
Magnetism is a class of physical phenomena that are mediated by magnetic fields.
Margaret Georgina Todd (23 April 1859 – 3 September 1918) was a Scottish doctor and writer.
Mass is both a property of a physical body and a measure of its resistance to acceleration (a change in its state of motion) when a net force is applied.
The mass number (symbol A, from the German word Atomgewichte (atomic weight), also called atomic mass number or nucleon number, is the total number of protons and neutrons (together known as nucleons) in an atomic nucleus. It determines the atomic mass of atoms. Because protons and neutrons both are baryons, the mass number A is identical with the baryon number B as of the nucleus as of the whole atom or ion. The mass number is different for each different isotope of a chemical element. This is not the same as the atomic number (Z) which denotes the number of protons in a nucleus, and thus uniquely identifies an element. Hence, the difference between the mass number and the atomic number gives the number of neutrons (N) in a given nucleus:. The mass number is written either after the element name or as a superscript to the left of an element's symbol. For example, the most common isotope of carbon is carbon-12, or, which has 6 protons and 6 neutrons. The full isotope symbol would also have the atomic number (Z) as a subscript to the left of the element symbol directly below the mass number:. This is technically redundant, as each element is defined by its atomic number, so it is often omitted.
Mass spectrometry (MS) is an analytical technique that ionizes chemical species and sorts the ions based on their mass-to-charge ratio.
The mass-to-charge ratio (m/Q) is a physical quantity that is most widely used in the electrodynamics of charged particles, e.g. in electron optics and ion optics.
In physics, mass–energy equivalence states that anything having mass has an equivalent amount of energy and vice versa, with these fundamental quantities directly relating to one another by Albert Einstein's famous formula: E.
Matrix mechanics is a formulation of quantum mechanics created by Werner Heisenberg, Max Born, and Pascual Jordan in 1925.
In the classical physics observed in everyday life, matter is any substance that has mass and takes up space by having volume.
In mathematical analysis, the maxima and minima (the respective plurals of maximum and minimum) of a function, known collectively as extrema (the plural of extremum), are the largest and smallest value of the function, either within a given range (the local or relative extrema) or on the entire domain of a function (the global or absolute extrema).
A metal (from Greek μέταλλον métallon, "mine, quarry, metal") is a material (an element, compound, or alloy) that is typically hard when in solid state, opaque, shiny, and has good electrical and thermal conductivity.
The Milky Way is the galaxy that contains our Solar System.
The mole, symbol mol, is the SI unit of amount of substance.
A molecular cloud, sometimes called a stellar nursery (if star formation is occurring within), is a type of interstellar cloud, the density and size of which permit the formation of molecules, most commonly molecular hydrogen (H2).
A molecule is an electrically neutral group of two or more atoms held together by chemical bonds.
In Newtonian mechanics, linear momentum, translational momentum, or simply momentum (pl. momenta) is the product of the mass and velocity of an object.
Monthly Notices of the Royal Astronomical Society (MNRAS) is a peer-reviewed scientific journal covering research in astronomy and astrophysics.
The muon (from the Greek letter mu (μ) used to represent it) is an elementary particle similar to the electron, with an electric charge of −1 e and a spin of 1/2, but with a much greater mass.
This article lists and discusses the usage and derivation of names of large numbers, together with their possible extensions.
The nanometre (International spelling as used by the International Bureau of Weights and Measures; SI symbol: nm) or nanometer (American spelling) is a unit of length in the metric system, equal to one billionth (short scale) of a metre (m).
The National Aeronautics and Space Administration (NASA) is an independent agency of the executive branch of the United States federal government responsible for the civilian space program, as well as aeronautics and aerospace research.
Nature is a British multidisciplinary scientific journal, first published on 4 November 1869.
A nebula (Latin for "cloud" or "fog"; pl. nebulae, nebulæ, or nebulas) is an interstellar cloud of dust, hydrogen, helium and other ionized gases.
In mathematics, a negative number is a real number that is less than zero.
Neon is a chemical element with symbol Ne and atomic number 10.
Neptunium is a chemical element with symbol Np and atomic number 93.
A neutrino (denoted by the Greek letter ν) is a fermion (an elementary particle with half-integer spin) that interacts only via the weak subatomic force and gravity.
Neutron capture is a nuclear reaction in which an atomic nucleus and one or more neutrons collide and merge to form a heavier nucleus.
The neutron–proton ratio (N/Z ratio or nuclear ratio) of an atomic nucleus is the ratio of its number of neutrons to its number of protons.
Nickel is a chemical element with symbol Ni and atomic number 28.
Niels Henrik David Bohr (7 October 1885 – 18 November 1962) was a Danish physicist who made foundational contributions to understanding atomic structure and quantum theory, for which he received the Nobel Prize in Physics in 1922.
Nitrogen is a chemical element with symbol N and atomic number 7.
The Nobel Foundation (Nobelstiftelsen) is a private institution founded on 29 June 1900 to manage the finances and administration of the Nobel Prizes.
The Nobel Prize (Swedish definite form, singular: Nobelpriset; Nobelprisen) is a set of six annual international awards bestowed in several categories by Swedish and Norwegian institutions in recognition of academic, cultural, or scientific advances.
The Nobel Prize in Physics (Nobelpriset i fysik) is a yearly award given by the Royal Swedish Academy of Sciences for those who conferred the most outstanding contributions for mankind in the field of physics.
The noble gases (historically also the inert gases) make up a group of chemical elements with similar properties; under standard conditions, they are all odorless, colorless, monatomic gases with very low chemical reactivity.
Nomenclature of Organic Chemistry, commonly referred to by chemists as the Blue Book, is a collection of recommendations on organic chemical nomenclature published at irregular intervals by the International Union of Pure and Applied Chemistry (IUPAC).
Nuclear binding energy is the minimum energy that would be required to disassemble the nucleus of an atom into its component parts.
In nuclear physics and nuclear chemistry, nuclear fission is either a nuclear reaction or a radioactive decay process in which the nucleus of an atom splits into smaller parts (lighter nuclei).
The nuclear force (or nucleon–nucleon interaction or residual strong force) is a force that acts between the protons and neutrons of atoms.
In nuclear physics, nuclear fusion is a reaction in which two or more atomic nuclei come close enough to form one or more different atomic nuclei and subatomic particles (neutrons or protons).
Nuclear Physics is a peer-reviewed scientific journal published by Elsevier.
In nuclear physics and nuclear chemistry, the nuclear shell model is a model of the atomic nucleus which uses the Pauli exclusion principle to describe the structure of the nucleus in terms of energy levels.
Nuclear transmutation is the conversion of one chemical element or an isotope into another chemical element.
In chemistry and physics, a nucleon is either a proton or a neutron, considered in its role as a component of an atomic nucleus.
Nucleosynthesis is the process that creates new atomic nuclei from pre-existing nucleons, primarily protons and neutrons.
A nuclide (from nucleus, also known as nuclear species) is an atomic species characterized by the specific constitution of its nucleus, i.e., by its number of protons Z, its number of neutrons N, and its nuclear energy state.
The observable universe is a spherical region of the Universe comprising all matter that can be observed from Earth at the present time, because electromagnetic radiation from these objects has had time to reach Earth since the beginning of the cosmological expansion.
Oganesson is a synthetic chemical element with symbol Og and atomic number 118.
The optical microscope, often referred to as the light microscope, is a type of microscope that uses visible light and a system of lenses to magnify images of small subjects.
In chemistry, an organic compound is generally any chemical compound that contains carbon.
Otto Hahn, (8 March 1879 – 28 July 1968) was a German chemist and pioneer in the fields of radioactivity and radiochemistry.
Otto Robert Frisch FRS (1 October 1904 – 22 September 1979) was an Austrian-British physicist.
The following outline is provided as an overview of and topical guide to chemistry: Chemistry – science of atomic matter (matter that is composed of chemical elements), especially its chemical reactions, but also including its properties, structure, composition, behavior, and changes as they relate the chemical reactions.
An oxide is a chemical compound that contains at least one oxygen atom and one other element in its chemical formula.
Oxygen is a chemical element with symbol O and atomic number 8.
Ozone, or trioxygen, is an inorganic molecule with the chemical formula.
Paramagnetism is a form of magnetism whereby certain materials are weakly attracted by an externally applied magnetic field, and form internal, induced magnetic fields in the direction of the applied magnetic field.
In the physical sciences, a particle (or corpuscule in older texts) is a small localized object to which can be ascribed several physical or chemical properties such as volume, density or mass.
A particle accelerator is a machine that uses electromagnetic fields to propel charged particles to nearly light speed and to contain them in well-defined beams.
In experimental and applied particle physics, nuclear physics, and nuclear engineering, a particle detector, also known as a radiation detector, is a device used to detect, track, and/or identify ionizing particles, such as those produced by nuclear decay, cosmic radiation, or reactions in a particle accelerator.
The Pauli exclusion principle is the quantum mechanical principle which states that two or more identical fermions (particles with half-integer spin) cannot occupy the same quantum state within a quantum system simultaneously.
The periodic table is a tabular arrangement of the chemical elements, ordered by their atomic number, electron configuration, and recurring chemical properties, whose structure shows periodic trends.
Periodic trends are specific patterns that are present in the periodic table that illustrate different aspects of a certain element, including its radius and its electronic properties.
The Philosophical Magazine is one of the oldest scientific journals published in English.
The photoelectric effect is the emission of electrons or other free carriers when light shines on a material.
The photon is a type of elementary particle, the quantum of the electromagnetic field including electromagnetic radiation such as light, and the force carrier for the electromagnetic force (even when static via virtual particles).
Physica Scripta is an international scientific journal for experimental and theoretical physics.
Physical Review is an American peer-reviewed scientific journal established in 1893 by Edward Nichols.
Physics Today is the membership magazine of the American Institute of Physics that was established in 1948.
The picometre (international spelling as used by the International Bureau of Weights and Measures; SI symbol: pm) or picometer (American spelling) is a unit of length in the metric system, equal to, or one trillionth of a metre, which is the SI base unit of length.
The Planck constant (denoted, also called Planck's constant) is a physical constant that is the quantum of action, central in quantum mechanics.
Plasma (Henry George Liddell, Robert Scott, A Greek English Lexicon, on Perseus) is one of the four fundamental states of matter, and was first described by chemist Irving Langmuir in the 1920s.
The plum pudding model is one of several scientific models of the atom.
Plutonium is a radioactive chemical element with symbol Pu and atomic number 94.
Plutonium-244 (244Pu) is an isotope of plutonium that has a half-life of 80 million years.
In modern mathematics, a point refers usually to an element of some set called a space.
In geometry, a position or position vector, also known as location vector or radius vector, is a Euclidean vector that represents the position of a point P in space in relation to an arbitrary reference origin O. Usually denoted x, r, or s, it corresponds to the straight-line from O to P. The term "position vector" is used mostly in the fields of differential geometry, mechanics and occasionally vector calculus.
The positron or antielectron is the antiparticle or the antimatter counterpart of the electron.
Potassium-40 (40K) is a radioactive isotope of potassium which has a very long half-life of 1.251 years.
In physics, potential energy is the energy possessed by an object because of its position relative to other objects, stresses within itself, its electric charge, or other factors.
A potential well is the region surrounding a local minimum of potential energy.
Pressure (symbol: p or P) is the force applied perpendicular to the surface of an object per unit area over which that force is distributed.
In geochemistry, geophysics and geonuclear physics, primordial nuclides, also known as primordial isotopes, are nuclides found on Earth that have existed in their current form since before Earth was formed.
In quantum mechanics, the principal quantum number (symbolized n) is one of four quantum numbers which are assigned to all electrons in an atom to describe that electron's state.
Proceedings of the National Academy of Sciences of the United States of America (PNAS) is the official scientific journal of the National Academy of Sciences, published since 1915.
Proceedings of the Royal Society is the parent title of two scientific journals published by the Royal Society.
Promethium is a chemical element with symbol Pm and atomic number 61.
In mathematics, two variables are proportional if there is always a constant ratio between them.
The mineral pyrite, or iron pyrite, also known as fool's gold, is an iron sulfide with the chemical formula FeS2 (iron(II) disulfide).
Quantum mechanics (QM; also known as quantum physics, quantum theory, the wave mechanical model, or matrix mechanics), including quantum field theory, is a fundamental theory in physics which describes nature at the smallest scales of energy levels of atoms and subatomic particles.
In quantum physics, quantum state refers to the state of an isolated quantum system.
Quantum tunnelling or tunneling (see spelling differences) is the quantum mechanical phenomenon where a particle tunnels through a barrier that it classically cannot surmount.
A quark is a type of elementary particle and a fundamental constituent of matter.
The rapid neutron-capture process, or so-called r-process, is a set of nuclear reactions that in nuclear astrophysics is responsible for the creation (nucleosynthesis) of approximately half the abundances of the atomic nuclei heavier than iron, usually synthesizing the entire abundance of the two most neutron-rich stable isotopes of each heavy element.
Radioactive decay (also known as nuclear decay or radioactivity) is the process by which an unstable atomic nucleus loses energy (in terms of mass in its rest frame) by emitting radiation, such as an alpha particle, beta particle with neutrino or only a neutrino in the case of electron capture, gamma ray, or electron in the case of internal conversion.
Radiochemistry is the chemistry of radioactive materials, where radioactive isotopes of elements are used to study the properties and chemical reactions of non-radioactive isotopes (often within radiochemistry the absence of radioactivity leads to a substance being described as being inactive as the isotopes are stable).
Radiometric dating or radioactive dating is a technique used to date materials such as rocks or carbon, in which trace radioactive impurities were selectively incorporated when they were formed.
A radionuclide (radioactive nuclide, radioisotope or radioactive isotope) is an atom that has excess nuclear energy, making it unstable.
Radium is a chemical element with symbol Ra and atomic number 88.
In cosmology, recombination refers to the epoch at which charged electrons and protons first became bound to form electrically neutral hydrogen atoms.
Review of Scientific Instruments is a monthly peer-reviewed scientific journal published by the American Institute of Physics.
Robert Brown FRSE FRS FLS MWS (21 December 1773 – 10 June 1858) was a Scottish botanist and palaeobotanist who made important contributions to botany largely through his pioneering use of the microscope.
The slow neutron-capture process or s-process is a series of reactions in nuclear astrophysics that occur in stars, particularly AGB stars.
Salt, table salt or common salt is a mineral composed primarily of sodium chloride (NaCl), a chemical compound belonging to the larger class of salts; salt in its natural form as a crystalline mineral is known as rock salt or halite.
A scanning tunneling microscope (STM) is an instrument for imaging surfaces at the atomic level.
In quantum mechanics, the Schrödinger equation is a mathematical equation that describes the changes over time of a physical system in which quantum effects, such as wave–particle duality, are significant.
Science, also widely referred to as Science Magazine, is the peer-reviewed academic journal of the American Association for the Advancement of Science (AAAS) and one of the world's top academic journals.
In chemistry, a silicate is any member of a family of anions consisting of silicon and oxygen, usually with the general formula, where 0 ≤ x Silicate anions are often large polymeric molecules with an extense variety of structures, including chains and rings (as in polymeric metasilicate), double chains (as in, and sheets (as in. In geology and astronomy, the term silicate is used to mean silicate minerals, ionic solids with silicate anions; as well as rock types that consist predominantly of such minerals. In that context, the term also includes the non-ionic compound silicon dioxide (silica, quartz), which would correspond to x.
SLAC National Accelerator Laboratory, originally named Stanford Linear Accelerator Center, is a United States Department of Energy National Laboratory operated by Stanford University under the programmatic direction of the U.S. Department of Energy Office of Science and located in Menlo Park, California.
Sodium chloride, also known as salt, is an ionic compound with the chemical formula NaCl, representing a 1:1 ratio of sodium and chloride ions.
The Solar SystemCapitalization of the name varies.
Solid is one of the four fundamental states of matter (the others being liquid, gas, and plasma).
A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from emission or absorption of light in a narrow frequency range, compared with the nearby frequencies.
Spectroscopy is the study of the interaction between matter and electromagnetic radiation.
The speed of light in vacuum, commonly denoted, is a universal physical constant important in many areas of physics.
In quantum mechanics and particle physics, spin is an intrinsic form of angular momentum carried by elementary particles, composite particles (hadrons), and atomic nuclei.
Spin polarization is the degree to which the spin, i.e., the intrinsic angular momentum of elementary particles, is aligned with a given direction.
In quantum physics, the spin–orbit interaction (also called spin–orbit effect or spin–orbit coupling) is a relativistic interaction of a particle's spin with its motion inside a potential.
Spontaneous emission is the process in which a quantum mechanical system (such as an atom, molecule or subatomic particle) transitions from an excited energy state to a lower energy state (e.g., its ground state) and emits a quantum in the form of a photon.
The term stable isotope has a meaning similar to stable nuclide, but is preferably used when speaking of nuclides of a specific element.
Stable nuclides are nuclides that are not radioactive and so (unlike radionuclides) do not spontaneously undergo radioactive decay.
The Standard Model of particle physics is the theory describing three of the four known fundamental forces (the electromagnetic, weak, and strong interactions, and not including the gravitational force) in the universe, as well as classifying all known elementary particles.
In physics, a standing wave – also known as a stationary wave – is a wave which oscillates in time but whose peak amplitude profile does not move in space.
A star is type of astronomical object consisting of a luminous spheroid of plasma held together by its own gravity.
The Stark effect is the shifting and splitting of spectral lines of atoms and molecules due to presence of an external electric field.
A stationary state is a quantum state with all observables independent of time.
Statistical physics is a branch of physics that uses methods of probability theory and statistics, and particularly the mathematical tools for dealing with large populations and approximations, in solving physical problems.
Stellar nucleosynthesis is the theory explaining the creation (nucleosynthesis) of chemical elements by nuclear fusion reactions between atoms within the stars.
The Stern–Gerlach experiment demonstrated that the spatial orientation of angular momentum is quantized.
Stimulated emission is the process by which an incoming photon of a specific frequency can interact with an excited atomic electron (or other excited molecular state), causing it to drop to a lower energy level.
In particle physics, the strong interaction is the mechanism responsible for the strong nuclear force (also called the strong force or nuclear strong force), and is one of the four known fundamental interactions, with the others being electromagnetism, the weak interaction, and gravitation.
In the physical sciences, subatomic particles are particles much smaller than atoms.
A supernova (plural: supernovae or supernovas, abbreviations: SN and SNe) is a transient astronomical event that occurs during the last stellar evolutionary stages of a star's life, either a massive star or a white dwarf, whose destruction is marked by one final, titanic explosion.
Synchrotron radiation (also known as magnetobremsstrahlung radiation) is the electromagnetic radiation emitted when charged particles are accelerated radially, i.e., when they are subject to an acceleration perpendicular to their velocity.
Technetium is a chemical element with symbol Tc and atomic number 43.
Temperature is a physical quantity expressing hot and cold.
Two physical systems are in thermal equilibrium if there are no net flow of thermal energy between them when they are connected by a path permeable to heat.
A timeline of atomic and subatomic physics.
Tin is a chemical element with the symbol Sn (from stannum) and atomic number 50.
Tin oxide may refer to.
Tin(II) oxide (stannous oxide) is a compound with the formula SnO.
Tin(IV) Oxide, also known as stannic oxide, is the inorganic compound with the formula SnO2.
In chemistry, transactinide elements (also, transactinides, or super-heavy elements) are the chemical elements with atomic numbers from 104 to 120.
Transmission electron microscopy (TEM, also sometimes conventional transmission electron microscopy or CTEM) is a microscopy technique in which a beam of electrons is transmitted through a specimen to form an image.
The transuranium elements (also known as transuranic elements) are the chemical elements with atomic numbers greater than 92 (the atomic number of uranium).
The triple-alpha process is a set of nuclear fusion reactions by which three helium-4 nuclei (alpha particles) are transformed into carbon.
Tritium (or; symbol or, also known as hydrogen-3) is a radioactive isotope of hydrogen.
In quantum mechanics, the uncertainty principle (also known as Heisenberg's uncertainty principle) is any of a variety of mathematical inequalities asserting a fundamental limit to the precision with which certain pairs of physical properties of a particle, known as complementary variables, such as position x and momentum p, can be known.
The unified atomic mass unit or dalton (symbol: u, or Da) is a standard unit of mass that quantifies mass on an atomic or molecular scale (atomic mass).
The University of Toronto (U of T, UToronto, or Toronto) is a public research university in Toronto, Ontario, Canada on the grounds that surround Queen's Park.
The up quark or u quark (symbol: u) is the lightest of all quarks, a type of elementary particle, and a major constituent of matter.
Uranium is a chemical element with symbol U and atomic number 92.
In chemistry, a valence electron is an outer shell electron that is associated with an atom, and that can participate in the formation of a chemical bond if the outer shell is not closed; in a single covalent bond, both atoms in the bond contribute one valence electron in order to form a shared pair.
In physics, in particular quantum mechanics, the vector model of the atom is a model of the atom in terms of angular momentum.
Water is a transparent, tasteless, odorless, and nearly colorless chemical substance that is the main constituent of Earth's streams, lakes, and oceans, and the fluids of most living organisms.
Wave–particle duality is the concept in quantum mechanics that every particle or quantic entity may be partly described in terms not only of particles, but also of waves.
A waveform is the shape and form of a signal such as a wave moving in a physical medium or an abstract representation.
In physics, the wavelength is the spatial period of a periodic wave—the distance over which the wave's shape repeats.
In particle physics, the weak interaction (the weak force or weak nuclear force) is the mechanism of interaction between sub-atomic particles that causes radioactive decay and thus plays an essential role in nuclear fission.
Werner Karl Heisenberg (5 December 1901 – 1 February 1976) was a German theoretical physicist and one of the key pioneers of quantum mechanics.
The whole number rule states that the masses of the isotopes are whole number multiples of the mass of the hydrogen atom.
Xenon is a chemical element with symbol Xe and atomic number 54.
The Zeeman effect, named after the Dutch physicist Pieter Zeeman, is the effect of splitting a spectral line into several components in the presence of a static magnetic field.
Ancient atom, Atom and Atomic Theory, Atomic chemical, Atomic structure, Atomic system, Atoms, Bound-bound, Bound-bound transition, Chemical Atom, Chemical atom, Monoelectronic, Multielectron atom, Number of atoms on Earth, Polyelectronic, Polyelectronic atoms, Structure of the atom.