An incorrect statement regarding resonating structures is : 

1.	The contributing structure must have the same number of unpaired electrons.
2.	The contributing structures should have similar energies.
3.	The resonance hybrid should have a higher energy than any of the contributing structures.
4.	None of the above.

An ion having  the shortest bond length among the following is -

1. $O_2^{+}$

2. $O_2^{-}$

3. $O_2^{2-}$

4. $O_2^{2+}$

Assuming that Hund's rule is violated, the bond order and magnetic nature of the diatomic molecule $B_2$ is:

The species having pyramidal shape is:

(1) $S{O}_3$

(2) $Br{F}_3$

(3) $Si{O}_3^{2-}$

(4) OSF₂

Among the following the maximum covalent character is shown by the compound:

(1) FeCl₂

(2) SnCl₂

(3) AlCl₃

(4) MgCl₂

Which of the following statement is wrong?

(1) The stability of hydrides increase from NH₃ to BiH₃ is group 15 of the periodic table.

(2) Nitrogen cannot form $d\mathrm{\pi }-\mathrm{p\pi }$ bond.

(3) Single N-N bond is weaker than the single P-P bond.

(4) $N_2{O}_4$ has four resonance structure

The structure of ${\mathrm{IF}}_7$ is

(1) square pyramid

(2) trigonal bipyramid

(3) octahedral

(4) pentagonal bipyramid

In which of the following pairs the two species are not isostructural?

(1) $PC{l}_4^{+} and SiC{l}_4$

(2) $P{F}_5 and Br{F}_5$

(3) $Al{F}_6^{3-}$ and $S{F}_6$

(4) $C{O}_3^{2-} and N{O}_3^{-}$

In allene $\left(C_3{H}_4\right),$ the type(s) of hybridization of the carbon atoms is (are):

1. sp and sp³

2.  sp and sp²

3. only sp²

4.  sp² and sp³

The shape of $Xe{O}_2{F}_2$ molecule is:

(1) trigonal bipyramidal

(2) square planar

(3) tetrahedral 

(4) see-saw