How to find the number of unpaired electrons?

[gokuls]

How do you find the number of unpaired electrons in a salt such as aluminum sulphate or ferrous sulphate. The number of unpaired of electron or bond order is needed to determine if something is paramagnetic.

 

[AGNuke]

Most anionic species and cationic species (amines, non-transition metals) have all paired electrons, like you asked, sulphate have no unpaired electron.

To find out unpaired electron in metals, you must write its configuration. Try writing the configuration of Al³⁺ and Fe²⁺, even try drawing orbital diagram of last orbital/last 2 orbitals to get a better picture.