Answer:
Valence electrons: P = 5, O =6, Cl = 7
The Lewis structure is shown below.
Explanation:
To determine the number of valence electrons, we need to find the atom at the periodic table, because the group determines this. P is at group 15 (or 5A), so it has 5 valence electrons, O is at group 16 (or 6A) so it has 6 valence electrons, and Cl is at group 17 (or 7A) so it has 7 valence electrons.
To follow the octet rule, all the atoms must have 8 electrons in the valence shell, so, P must do 3 bonds, O two, and Cl one. So, the most likely formula is P with a single bond with O, and with two Cl, and the other Cl with a single bond with O.
There'll be 1 lone pair in P, 2 lone pairs in O, and 3 lone pairs in each Cl atom, as shown below.
The Lewis structure is done by placing the atoms with their valence electrons represented and then making the bonds, as shown below.
