Question

How do you determine if an atom has a diamagnetic (ground state) electron configuration?

Answer 1

By checking out the arrangement of it's valence electrons in it's outer most orbital.

Explanation:

The arrangement of the electrons in the outermost orbital i.e `s, p, d, or f` determines the dimagnetic or paramagnetic character of an atom.
A dimagnetic atom has all the electrons arranged in pairs
Where as a paramagnetic atom have more than 1 umpaired electrons.
And the magnetic moment of paramagnetic atom can be calculated by the formula.

`mu = [√n(n+2)]`

Hope it will help you.