(i) S and S2– The number of valence electrons in sulphur is 6. The Lewis dot symbol of sulphur (S) is 
.
The dinegative charge infers that there will be two electrons more in addition to the six valence electrons.Hence, the Lewis dot symbol of S2– is
.
(ii) Al and Al3+ The number of valence electrons in aluminium is 3. The Lewis dot symbol of aluminium (Al) is
. The tripositive charge on a species infers that it has donated its three electrons. Hence, the Lewis dot symbol is
.
(iii) H and H– The number of valence electrons in hydrogen is 1. The Lewis dot symbol of hydrogen (H) is
. The uninegative charge infers that there will be one electron more in addition to the one valence electron. Hence, the Lewis dot symbol is
.
