In $P{O}_4^{-3}$, formal charge on every oxygen atom and P-O bond order respectively are:
1. –0.75 and 1.25
2. –0.5 and 2
3. 1 and 1.5
4. –0.75 and 2

Which of the following compounds is electron deficient?

1. BaCl₂

2. BCl₃

3. CCl₄

4. PCl₅

Which of the following sets consists of isoelectronic species?

1. CO, CN^–, NO⁺, C₂^2–

2. CO^–, CN, NO, C₂^–

3. CO⁺, CN⁺, NO^–, C₂

4. CO, CN, NO, C₂

Select the pair of isostructural species:

Identify the isoelectronic pair among the following: