For SiCl₄,
First before we start this problem we would have to count the total valence electrons on each atom that is coming from the a molecule.
The valence electron of Si would = 4.
The valence electron of Cl would = 7.
So to find the total valence electrons of SiCl₄ you would have to do
4 + 4 x 7 = 32
Then we would have to find the least electronegative atom of the molecule and place that at the center
In SiCl₄, Si has 1.8 and Cl has 3.16
Which means a single bond would to take 2 valence electrons and so for 4 bonds their would be 8 valence electrons that would have to be occupied. Which would leave us with 32 - 8 = 24 valence electrons.
So your answer of SiCl₄ would be 24.
Hope this helps
