Why is the chloride ion shown as containing only 3 lone pairs?
It does have the four lone pairs, does it not?
An isolated chlorine ATOM has 7 valence electrons. And thus the parent dichlorine molecule tends to be an OXIDANT, viz......
And because the resultant chloride anion has FOUR SUCH LONE PAIRS, instead of the SEVEN electrons associated with the NEUTRAL atom, chloride has a FORMAL NEGATIVE CHARGE.
Sorry for all the SHOUTING; there are a few points worth EMPHASIZING.
How are these four lone pairs distributed? That is, how would you predict electronic geometry?