Electron cloud is a term used for introducing the concept of wavefunction in low-level pedagogical introductions to atomic physics, molecular physics, chemistry or quantum chemistry. This idea corresponds to delocated electrons moving or standing like clouds around the atomic or molecular nuclei. This is indeed a better image than the very common image provided by the Bohr model which commonly leads to a visualisation of electrons driving around the nuclei along orbits like the planets around the sun. This article discusses the concept of a wavefunction as it relates to quantum mechanics. ... Atomic physics (or atom physics) is the field of physics that studies atoms as isolated systems comprised of electrons and atomic nuclei. ... Molecular physics is the study of the physical properties of molecules and of the chemical bonds between atoms that bind them into molecules. ... Multicolored chemicals are frequent hallmarks of chemistry. ... Linus Pauling, as a pioneer of the valence bond theory, is one of the first quantum chemists. ... Properties The electron is a fundamental subatomic particle that carries a negative electric charge. ... A stylized representation of a lithium atom. ... In general, a molecule is the smallest particle of a pure chemical substance that still retains its composition and chemical properties. ... The Bohr model of the atom In atomic physics, the Bohr model depicts the atom as a small, positively charged nucleus surrounded by waves of electrons in orbit - similar in structure to the solar system, but with electrostatic forces providing attraction, rather than gravity, and with waves spread over entire... In physics, an orbit is the path that an object makes, around another object, whilst under the influence of a source of centripetal force, such as gravity. ... A planet is generally considered to be a relatively large mass of accreted matter in orbit around a star that is not a star itself. ... The Sun is the spectral type G2V yellow star at the center of Earths solar system. ...

This representation is related to the idea that the electrons are not precisely located around the atomic or molecular nuclei but must instead be described by probability amplitudes or wavefunctions which provides the probability to find electrons in a given region of space (for example along a particular chemical bond). These mathematical functions of the coordinates of all electrons are often expressed in terms of electronic configurations or Slater determinants which are in turn expressed in terms of atomic or molecular orbitals. One can represent the theory also in terms of the electron density which is a function of one electron only. This approach is called the density functional theory. Both the molecular orbital and density functional approaches are the basic elements of modern quantum chemistry and of computational chemistry. Properties The electron is a fundamental subatomic particle that carries a negative electric charge. ... In quantum mechanics, a probability amplitude is a complex number-valued function which describes an uncertain or unknown quantity. ... The word probability derives from the Latin probare (to prove, or to test). ... A chemical bond is the physical phenomenon of chemical substances being held together by attraction of atoms to each other through sharing, as well as exchanging, of electrons -or electrostatic forces. ... Partial plot of a function f. ... See Cartesian coordinate system or Coordinates (elementary mathematics) for a more elementary introduction to this topic. ... Electron configuration is the arrangement of electrons in an atom, molecule or other body. ... A Slater determinant (named after the physicist John C. Slater) is an expression in quantum mechanics for the wavefunction of a many-fermion system, which by construction satisfies the Pauli principle. ... Electron atomic and molecular orbitals A less formal description of the electrons in atoms can be found at Electron configuration. ... Electron atomic and molecular orbitals In quantum chemistry, the molecular electronic states, i. ... Electron density is the measure of the probability of an electron being present at a specific location. ... Density functional theory (DFT) is one of the most popular approaches to quantum mechanical many-body electronic structure calculations of molecular and condensed matter systems. ... Linus Pauling, as a pioneer of the valence bond theory, is one of the first quantum chemists. ... // Computational chemistry is a branch of theoretical chemistry whose major goals are to create efficient mathematical approximations and computer programs that calculate the properties of molecules (such as total energy, dipole and quadrupole moment, vibrational frequencies, reactivity and other diverse spectroscopic quantitities and cross sections for collision of molecules with...