Question

1.) What is the difference of a Lewis Dot Structure and the structure formula?? Is one (structure formula) the step by step procedure of making a lewis dot structure?

2) I tried doing the Lewis dot for SiCl4 I didn't get any lone pairs, and I said the molecular geometry was a Square planar. However, the molecular geometry was (on my professor's answer sheet) Tetrahedral. Why is that?

Answer 1

1) The structure formula shows the bonds, dot structure shows all the valence electrons.
2) We know that Si is bonded to 4 Cl atoms. That means, there are 4 bonds already present. In a dot structure, a bond consists of a lone pair (2 electron dots). So, we first label the Si and Cls and dot the bonds.