Question

Fill in the blanks.

The valency of iron in $FeC{l}_3$ is ......................

Answer 1

In iron trichloride the valence of iron is +3 and the valence of chlorine -1. Consider of iron(III) with valency 3 having 3 hooks. Then Cl with valency 1 with only one hook.

So we just swap the numbers round and get $Fe1Cl3$ which is the formulae.