Question

part a
n2o
spell out the full name of the compound.
part b
no
spell out the full name of the compound.
part c
no2

Explanation:

In naming binary covalent compounds, prefixes are used to indicate the number of each type of atom. For $N_2O$, there are 2 nitrogen atoms (prefix "di -") and 1 oxygen atom (prefix "mono -", but mono - is often omitted for the first - named element). For NO, there is 1 nitrogen atom (prefix not used as first - named element) and 1 oxygen atom (prefix "mono -"). For $NO_2$, there is 1 nitrogen atom (prefix not used) and 2 oxygen atoms (prefix "di -").

Answer:

Part A: Dinitrogen monoxide
Part B: Nitrogen monoxide
Part C: Nitrogen dioxide