The atomic orbital concept is therefore a key concept for visualizing the excitation process associated to a given transition. This notation means that the corresponding Slater determinants have a clear higher weight in the configuration interaction expansion. 1 s 2 2 s 2 2 p 6 for the ground state of neon - term symbol: 1S 0). by occupations schemes of atomic orbitals (e.g. These states are labelled by a set of quantum numbers summarized in the term symbol and usually associated to particular electron configurations, i.e. In atomic physics, the atomic spectral lines correspond to transitions (quantum leaps) between quantum states of an atom. (When one considers also their spin component, one speaks of atomic spin orbitals.) The spatial components of these one-electron functions are called atomic orbitals. the eigenstates of the atomic Hamiltonian, is expanded (see configuration interaction expansion and basis (linear algebra)) into linear combinations of anti-symmetrized products (Slater determinants) of one- electron functions. In quantum mechanics, the state of an atom, i.e. , the letters associated with those numbers are K, L, M, N, O. In some cases, the principal quantum number is given a letter associated with it. Where X is the energy level corresponding to the principal quantum number n, type is a lower-case letter denoting the shape or subshell of the orbital and it corresponds to the angular quantum number l, and y is the number of electrons in that orbital.įor example, the orbital 1 s 2 ( pronounced "one ess two") has two electrons and is the lowest energy level ( n = 1) and has an angular quantum number of l = 0. 8 Electron placement and the periodic table.For mnemonic reasons, some call them spherical & peripheral. The orbital names (s, p, d, f, g, h.) are derived from the characteristics of their spectroscopic lines: sharp, principal, diffuse and fundamental, the rest being named in alphabetical order. Hence the term "orbit" was substituted with something else: orbital. As electrons cannot be described as solid particles (as a planet or a moth) in this way, a more accurate analogy would be that of a huge atmosphere, the spatially distributed electron, around a tiny planet which is the atomic nucleus. In quantum mechanics, atomic orbitals are described as wave functions over space, indexed by the n, l, and m quantum numbers of the orbital or by the names as used in electron configurations, as shown on the right. Explaining the behavior of the electrons that "orbit" an atom was one of the driving forces behind the development of quantum mechanics. Specifically, atomic orbitals are the possible quantum states of an individual electron in the electron cloud around a single atom, as described by the function.Ĭlassically, the electrons were thought to orbit the atomic nucleus, much like the planets around the Sun (or more accurately, a moth orbiting very quickly around a lamp). The term "orbital" has become known as either the "mathematical function" or the "region" generated with the function.
The region in which an electron may be found around a single atom in a particular energy state can be calculated from this function. An atomic orbital is a mathematical function that describes the wave-like behavior of an electron in an atom.