The bond angles $b_1, b_2$ and $b_3$ in the given structure are respectively (in ${ }^{\circ}$ )

In which of the following sets of molecules, the centil atoms of molecules have same hybridisation?

The correct increasing order of number of lone pair of electrons on the central atom of $\mathrm{SnCl}_2, \mathrm{XeF}_2, \mathrm{CIF}_3$ and $\mathrm{SO}_3$ is

The bond lengths of diatomic molecules of elements $X$, $Y$ and $Z$ respectively are 143, 110 and 121 pm . The atomic numbers of $X, Y$, and $Z$ respectively are