The number of molecules/ion/s having trigonal bipyramidal shape is _______.

$\mathrm{PF}_5, \mathrm{BrF}_5, \mathrm{PCl}_5,\left[\mathrm{Pt} \mathrm{Cl}_4\right]^{2-}, \mathrm{BF}_3, \mathrm{Fe}(\mathrm{CO})_5$

The lowest oxidation number of an atom in a compound $\mathrm{A}_2 \mathrm{B}$ is -2 . The number of electrons in its valence shell is _______.

A diatomic molecule has a dipole moment of $$1.2 \mathrm{~D}$$. If the bond distance is $$1 \mathrm{~A}^{\circ}$$, then fractional charge on each atom is _________ $$\times 10^{-1}$$ esu.

(Given $$1 \mathrm{~D}=10^{-18}$$ esucm)

The number of species from the following in which the central atom uses $$\mathrm{sp}^3$$ hybrid orbitals in its bonding is __________.

$$\mathrm{NH}_3, \mathrm{SO}_2, \mathrm{SiO}_2, \mathrm{BeCl}_2, \mathrm{CO}_2, \mathrm{H}_2 \mathrm{O}, \mathrm{CH}_4, \mathrm{BF}_3$$