For the reaction,

$$\mathrm{H}_{2(g)}+\mathrm{Br}_{2(8)} \longrightarrow 2 \mathrm{HBr}_{(\mathrm{g})}, \mathrm{r}=\mathrm{k}\left[\mathrm{H}_2\right]\left[\mathrm{Br}_2\right]^{\frac{1}{2}}$$

What is the molecularity and order of reaction respectively?

Identify an actinoid element from following.

What is the oxidation number of Mn in $\mathrm{MnO}_4^{-}$?

What is the number of electrons present in antibonding orbitals of $\mathrm{N}_2$ molecule according to molecular orbital theory?