How can you tell how many electrons orbital shells an element has?

Answer 1

The number of orbitals is easy. Find out the number of electrons (atomic number) and then separate it into the relevant shells. GCSE: you are required only to know the electron configuration e.g. 2.8.8.... A-Level: sort it into sub-levels 1s, 2s, 2p, 3s, 3p, 4s, 3d.... Ok, so if you are taking the element Mg into consideration GCSE: 2.8.2 A-Level: 3 row down (so 3rd sub-shell) and the s-block of the Periodic Table 1s2, 2s2, 2p6, 3s2 Finito!

Answer 2

You can determine the number of electrons in an element's orbital shells by looking at its atomic number, which tells you the number of protons and electrons in a neutral atom. The electron configuration of an element provides a more detailed breakdown of how the electrons are distributed among the different orbital shells.