The correct order of ionic character among CaH₂, BeH₂ and BaH₂ is:

1.	BeH2 < CaH2 < BaH2	2.	CaH2 < BeH2 < BaH2
3.	BeH2 < BaH2 < CaH2	4.	BaH2 < BeH2 < CaH2

Mark the correct order of repulsion among the following according to the VSEPR theory.

The decreasing order of stability of ${\mathrm{O}}_2,{\mathrm{O}}_2^{-},{\mathrm{O}}_2^{+}$ $\mathrm{and}$ ${\mathrm{O}}_2^{2-}$is: 

1. ${\mathrm{O}}_2^{+}>{\mathrm{O}}_2>{\mathrm{O}}_2^{-}>{\mathrm{O}}_2^{2-}$

2. ${\mathrm{O}}_2^{2-}>{\mathrm{O}}_2^{-}>{\mathrm{O}}_2>{\mathrm{O}}_2^{+}$

3. ${\mathrm{O}}_2>{\mathrm{O}}_2^{+}>{\mathrm{O}}_2^{2-}>{\mathrm{O}}_2^{-}$

4. ${\mathrm{O}}_2^{-}>{\mathrm{O}}_2^{2-}>{\mathrm{O}}_2^{+}>{\mathrm{O}}_2$

Which of the following species contains an equal number of $\mathrm{\sigma }$ and $\mathrm{\pi }$ bonds?

1. ${\mathrm{HCO}}_3^{-}$

2. ${\mathrm{XeO}}_4$

3. ${\left(\mathrm{CN}\right)}_2$

4. CH₂(CN)₂

Choose the compound which has a maximum bond angle at nitrogen among the following:
1. ${\mathrm{NO}}_2$
2. ${{\mathrm{NO}}_2}^{-}$
3. ${{\mathrm{NO}}_2}^{+}$
4. ${{\mathrm{NO}}_3}^{-}$

The correct order of bond order in the following species is: