What is the formal charge on a hydrogen atom in a water molecule?

What is the main difference between an ionic bond and a covalent bond?

Which of the following does not obey the octet rule?

Total number of non-bonded electrons present in $NO_2^{-}$ ion based on Lewis theory is $........$

Fill in the blanks given below:
$(i)$ The energy required to completely separate one mole of a solid ionic compound into its gaseous constituent ions is called ........... .
$(ii)$ The angle formed between the orbitals containing bonding electrons around the central atom is called ........... .
$(iii)$ The energy required to break one mole of bonds is called ........... .
$(iv)$ The $VSEPR$ theory was proposed by scientists ............ and ........... .

The total number of right angles $\angle ClPCl$ present in $PCl_5$,$PCl_4^+$,and $PCl_6^-$ are . . . . . . , . . . . . . , . . . . . . respectively.