Question

2. Which one of the following pair of molecules or species is not isoelectronic pair?
A. CO and N2 B. NH3 and H3O+ C. N2 and CN- D. CO2 and SO2
3. Which covalent molecule contains more number of total valance electrons than the others?
A. SO4 -2 B. NH4+ C. N2O4 D. CO2
4. Which of the following is the correct Lewis Structure for oxygen atom?
A. The three lone-pairs of valance electrons.
B. One lone-pair of valance electrons and one bonding site.
C. Two lone-pair of valance electrons and one bonding site.
D. Two lone-pair of valance electrons and two bonding site.

Answer 1

2. C. N2 and CN- (N2 has 10 electrons, CN- has 8 electrons)
3. C. N2O4 (contains 36 total valence electrons)
4. C. Two lone-pair of valance electrons and one bonding site.