Show all the lone pairs of electrons in the skeletal structure below.

Sulfur (S) has 6 valence shell electrons and forms 3 new bonds. Is this true?

Supply all the lone pairs of electrons in the following skeletal structure. 

Determine the number of lone pairs in the marked atoms of the following molecular structures.

Determine the number of valence electrons in the atoms given below.

a. Beryllium
b. Aluminium

Based on their position on the periodic table, how many core and valence electrons do the following elements have?

(i) Arsenic

(ii) Antimony

(iii) Strontium

(iv) Beryllium