Electronic structure
From Wikiversity
Electrons were believed to be particles until Louis de Broglie in 1924 suggested they have wavelike properties as well. A few years later Schrödinger calculated the energy of an electron in a hydrogen atom by using an equation that treated the electron like a wave. He obtained a series of energy levels, instead of a single energy — which means we can't tell where exactly an electron is located. We can only know where the electron is likely to be.
Classical (Newtonian) Structure
The basic electronic structure of atoms is that of energy levels, also called shells. These levels are certain distances away from the nucleus of the atom; the higher the level, the higher the energy of the electrons. The first energy level can hold up to two electrons, the second can hold up to eight, the third can hold 18, the fourth can hold 32, and shell n can hold 2n2. For neutral atoms (those with no charge), the number of electrons is equal to the atomic number of the atom.
