1. Show that NinNF3 obeys the octet rule. 2. Show that Se in H2 Se obeys the octet rule. 3. In which of the following molecules is the octet rule apparently violated by the central atom: (a) H2S; (b) HCN; (c) SO2; (d) CO2; (e) SO3 ? [ Ans. (c); (e)] 4. Within the series of fluorides IF,IF3 and IF5, show that the octet rule appears to be obeyed in only one instance for iodine