<Li> The electrons retain particle - like properties such as: each wave state has the same electrical charge as the electron particle . Each wave state has a single discrete spin (spin up or spin down). This can depend upon its superposition . </Li> <P> Thus, despite the popular analogy to planets revolving around the Sun, electrons cannot be described simply as solid particles . In addition, atomic orbitals do not closely resemble a planet's elliptical path in ordinary atoms . A more accurate analogy might be that of a large and often oddly shaped "atmosphere" (the electron), distributed around a relatively tiny planet (the atomic nucleus). Atomic orbitals exactly describe the shape of this "atmosphere" only when a single electron is present in an atom . When more electrons are added to a single atom, the additional electrons tend to more evenly fill in a volume of space around the nucleus so that the resulting collection (sometimes termed the atom's "electron cloud") tends toward a generally spherical zone of probability describing where the atom's electrons will be found . This is due to the uncertainty principle . </P> <P> Atomic orbitals may be defined more precisely in formal quantum mechanical language . Specifically, in quantum mechanics, the state of an atom, i.e., an eigenstate of the atomic Hamiltonian, is approximated by an expansion (see configuration interaction expansion and basis set) into linear combinations of anti-symmetrized products (Slater determinants) of one - electron functions . The spatial components of these one - electron functions are called atomic orbitals . (When one considers also their spin component, one speaks of atomic spin orbitals .) A state is actually a function of the coordinates of all the electrons, so that their motion is correlated, but this is often approximated by this independent - particle model of products of single electron wave functions . (The London dispersion force, for example, depends on the correlations of the motion of the electrons .) </P> <P> In atomic physics, the atomic spectral lines correspond to transitions (quantum leaps) between quantum states of an atom . These states are labeled by a set of quantum numbers summarized in the term symbol and usually associated with particular electron configurations, i.e., by occupation schemes of atomic orbitals (for example, 1s 2s 2p for the ground state of neon--term symbol: S). </P>

Who developed the idea of electron shells also known as orbital shells