Question

Indicate the number of unpaired electrons in P.

Answer 1

Step 1: Writing the electronic configuration

The electronic configuration of Phosphorus is: $1{\mathrm{s}}^{2}2{\mathrm{s}}^{2}2{\mathrm{p}}^{6}3{\mathrm{s}}^{2}3{\mathrm{p}}^3$

Thus we can see that it has 5 valence electrons in its outermost shell.

Step 2: Calculating the unpaired electrons

In Phosphorus, the p-subshell has 3 electrons in it.

Now we know that these electrons will fill the orbitals according to Hund's rule of maximum multiplicity

That is the orbitals will first be filled singly and after all the orbitals are filled singly, then the pairing of the electrons will start.

For Phosphorus, if we draw the 3s and 3p orbital:

Here we can see that in the 3p orbital, there are 3 unpaired electrons present.

Therefore, Phosphorus has 3 unpaired electrons present in it.