What is the particle unit for so42-?

The particle unit is an ion.

Explanation: The unit which is common used for the substances is Mole. 1 mole of anything equals to Avogadro number which is .

For example, 1 mole of an electron equals to electrons,

1 mole of an atom equals to atoms.

So, 1 mole equals to particles.

is sulfate ion. So, the particle unit for this will be an ion.

why do the isotopes of a particular element behave differently in nuclear reactions but the same in chemical reactions? chemical reactions involve changes to electrons in an atom; isotopes do not differ in electrons, and so they react the same way during chemical changes.