Electron Orbitals & Sub-shells
- Each shell can be divided further into subshells, labelled s, p, d and f
- Each subshell can hold a specific number of orbitals:
- s subshell : 1 orbital
- p subshell : 3 orbitals labelled px, py and pz
- d subshell : 5 orbitals
- f subshell : 7 orbitals
- Each orbital can hold a maximum number of 2 electrons so the maximum number of electrons in each subshell are as follows:
- s : 1 x 2 = total of 2 electrons
- p : 3 x 2 = total of 6 electrons
- d : 5 x 2 = total of 10 electrons
- f : 7 x 2 = total of 14 electrons
- In the ground state, orbitals in the same subshell have the same energy and are said to be degenerate, so the energy of a px orbital is the same as a py orbital
Detailed summary of electron shells
Shells are divided into subshells which are further divided into orbitals
Summary of the arrangement of electrons in atoms
Principal quantum number, n (shell) |
Sub-shells possible (s, p, d, f) |
Orbitals per sub-shell | Orbitals per principal quantum number | Electrons per sub-shells | Electrons per shell |
1 | s | 1 | 1 | 2 | 2 |
2 | s | 1 | 4 | 2 | 8 |
p | 3 | 6 | |||
3 | s | 1 | 9 | 2 | 18 |
p | 3 | 6 | |||
d | 5 | 10 | |||
4 | s | 1 | 16 | 2 | 32 |
p | 3 | 6 | |||
d | 5 | 10 | |||
f | 7 | 14 |