cloud of electrons -
21Atomic theory — Atomic model redirects here. For the unrelated term in mathematical logic, see Atomic model (mathematical logic). This article is about the historical models of the atom. For a history of the study of how atoms combine to form molecules, see… …
22chemical element — Introduction also called element, any substance that cannot be decomposed into simpler substances by ordinary chemical processes. Elements are the fundamental materials of which all matter is composed. This article considers the… …
23Hückel's rule — In organic chemistry, Hückel s rule estimates whether a planar ring molecule will have aromatic properties. The quantum mechanical basis for its formulation was first worked out by physical chemist Erich Hückel in 1931. It was first expressed… …
24subatomic particle — or elementary particle Any of various self contained units of matter or energy. Discovery of the electron in 1897 and of the atomic nucleus in 1911 established that the atom is actually a composite of a cloud of electrons surrounding a tiny but… …
25Polywell — The polywell is a plasma confinement concept that combines elements of inertial electrostatic confinement and magnetic confinement fusion, intended ultimately to produce fusion power. The name polywell is a portmanteau of polyhedron and potential …
26Atomic radius — Diagram of a helium atom, showing the electron probability density as shades of gray. The atomic radius of a chemical element is a measure of the size of its atoms, usually the mean or typical distance from the nucleus to the boundary of the… …
27Electron avalanche — An electron avalanche is a process in which a number of free electrons in a medium (usually a gas) are subjected to strong acceleration by an electric field, ionizing the medium s atoms by collision (called impact ionization), thereby forming new …
28Hasegawa-Mima equation — The Hasegawa Mima equation, named after Akira Hasegawa and Kunioki Mima, is an equation that describes a certain regime of plasma, where the time scales are very fast, and the distance scale in the direction of the magnetic field is long. In… …
29electric dipole — Pair of equal and opposite electric charges, the centres of which do not coincide. An atom in which the centre of the negative cloud of electrons has been shifted slightly away from the nucleus by an external electric field is an induced electric …
30List of particles — This is a list of the different types of particles, known and hypothesized. For a chronological listing of subatomic particles by discovery date, see Timeline of particle discoveries. This is a list of the different types of particles found or… …
