Among the following, iso-electronic species are:

1. CO₂, NO₂

2. $N{O}_2^{-}$, CO₂

3. CN^–, CO

4. SO₂, CO₂

In NO₃^– ion, the number of bond pair and lone pair of electrons on nitrogen atom are respectively:

The incorrect statements among the following for sigma- and pi- bonds formed between two carbon atoms is:

The driving force of an atom to form chemical bonds involves:
1. To increase the size.
2. To decrease size.
3. To attain stability.
4. None of the above.

The Lewis dot symbols for atoms of the elements Mg, Na, O, and N, respectively, would be:

1.
2.
3.
4.

Lewis symbols for the atoms and ions: S and S^2–; Al and Al³⁺; H and H^– respectively, would be:

1.
2.
3.
4.

Which of the following factors are favourable for the formation of an ionic bond?

The correct relationship between bond strength and bond order is :

The bond length can be defined as: