In the $15^{th}$ group of the periodic table,the elements $N, P, As, Sb$,and $Bi$ are present. As we move from $N$ to $Bi$,how do the oxides with the general formula change?

Which of the nitrogen oxides is obtained when ammonium nitrate is heated?

Given below are the two statements: one is labeled as Assertion $(A)$ and the other is labeled as Reason $(R)$.
Assertion $(A)$: There is a considerable increase in covalent radius from $N$ to $P$. However,from $As$ to $Bi$,only a small increase in covalent radius is observed.
Reason $(R)$: Covalent and ionic radii in a particular oxidation state increase down the group.
In the light of the above statements,choose the most appropriate answer from the options given below:

Which of the following pentahalides is $NOT$ formed?

Which of the following compounds on heating gives $N_{2}O$?

The nitrogen oxide$(s)$ that contain$(s)$ $N-N$ bond$(s)$ is(are):
$A$. $N_2O$
$B$. $N_2O_3$
$C$. $N_2O_4$
$D$. $N_2O_5$