Question

8. How many unpaired electrons does Zn2+ have?

Answer 1

Zinc (Zn) has atomic number 30.

Hence, the electronic configuration of zinc is

Zn: 1s2 2s2 2p6 3s2 3pნ 42 3d10

To form the Zn2+ ion, we need to take out 2 electrons from the outermost shell. The outermost shell in Zn is the 4s orbital.

Hence, the electronic configuration of the $Zn^{2+}$ ion will be

Zn2+ : 1s2 2s2 2p6 3s2 3pნ 4s 3d18

Note that all the occupied orbitals in the ion are fully filled(even number of electrons on every subshell). Since electrons in a fully filled orbitals are always paired, there are no unpaired electron in $Zn^{2+}$ .

Hence, the number of unpaired electron in $Zn^{2+}$   ion is zero.