Given below are the oxides :
$$Na_2O, As_2O_3, N_2O, NO$$ and $$Cl_2O_7$$
Number of amphoteric oxides is :

We need to determine how many of the given oxides are amphoteric.

The given oxides are: $$Na_2O$$, $$As_2O_3$$, $$N_2O$$, $$NO$$, and $$Cl_2O_7$$.

1. $$Na_2O$$ (Sodium oxide): Na is a strongly electropositive alkali metal. $$Na_2O$$ is a basic oxide. It reacts with water to form NaOH and reacts with acids but not with bases.

2. $$As_2O_3$$ (Arsenic trioxide): Arsenic is a metalloid. $$As_2O_3$$ is an amphoteric oxide. It reacts with both acids and bases:

$$As_2O_3 + 6HCl \rightarrow 2AsCl_3 + 3H_2O$$ (reacts with acid)

$$As_2O_3 + 6NaOH \rightarrow 2Na_3AsO_3 + 3H_2O$$ (reacts with base)

3. $$N_2O$$ (Nitrous oxide): This is a neutral oxide. It does not react with either acids or bases.

4. $$NO$$ (Nitric oxide): This is a neutral oxide. It does not react with either acids or bases.

5. $$Cl_2O_7$$ (Dichlorine heptoxide): This is the anhydride of perchloric acid ($$HClO_4$$). It is a strongly acidic oxide.

Therefore, only $$As_2O_3$$ is amphoteric. The number of amphoteric oxides = 1.

The correct answer is Option B: 1.