The correct formula of aluminium perchlorate is _______.

With the help of Lewis dot structure, find the number of total covalent bonds in species. 

(i)${\mathrm{CO}}_3^{2-}$, (ii) ${\mathrm{CCl}}_4$, (iii) ${\mathrm{NF}}_3$
 

Indicate what is wrong with each of the following Lewis structures. Replace each with a more acceptable structure. 

In how many of the following species, the central atoms have two lone pairs of electrons?

(i) ${\mathrm{XeF}}_4$
(ii) ${\mathrm{XeF}}_5$
(iii) ${\mathrm{F}}_2{\mathrm{SeO}}_2$
(iv) ${\mathrm{XeF}}_{3^{*}}$
(V) ${\mathrm{XeOF}}_4$
(vi) ${\mathrm{ClOF}}_3$
(vii) ${\mathrm{ICl}}_4-$
(viii) ${\mathrm{SCl}}_2$
(ix) ${\mathrm{SCl}}_2$

How many compounds violate octet rule? 

(i)${\mathrm{CO}}_2$
(ii) $\mathrm{PCls}$
(iii) ${\mathrm{SiF}}_4$
(iv) $\mathrm{Bf}\overline{5} \mathrm{s}$
(v) ${\mathrm{IF}}_7$
(vi) ${\mathrm{PCl}}_3$
(vi) ${\mathrm{H}}_2{\mathrm{SO}}_4$friii) ${\mathrm{BF}}_3$