(i) S and S2– Electronic configuration of S is [Ne]¹⁰ 3s²3p⁴, i.e it has 6 electrons in its valence shell,therefore The Lewis dot symbol of sulphur (S) is . The dinegative charge shows that there will be two electrons more in addition to the six valence electrons. The electronic configuration can be [Ne]¹⁰ 3s²3p⁶, Hence, the Lewis dot symbol of S2– is .

(ii) Al and Al3+ The electronic configuration of Aluminium is [Ne]¹⁰ 3s² 3p¹, i.e the valence electron is 3,therefore The Lewis dot symbol of aluminium (Al) is . The tripositive charge on a species infers that it has donated its three electrons to other atom & its possible electronic configuration is [Ne]¹⁰ 3s¹. Hence, the Lewis dot symbol is .

(iii) H and H– Hydrogen has electronic configuration of 1s¹,it has 1 electron in its valence shell. 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. The possible configuration may be 1s2. Hence, the Lewis dot symbol is .