The charge on an atom containing $17$ protons,$18$ neutrons,and $18$ electrons is = .......

Which of the following are identical in terms of their atomic number $(Z)$?
$(i)$ $Na$ and $Na^+$
$(ii)$ $F$ and $F^-$

Compared with an atom of atomic weight $12$ and atomic number $6$,the atom of atomic weight $13$ and atomic number $6$:

Which of the following are pairs of isotopes?

The atomic configurations of atoms $A$,$B$,and $C$ are given as: $A = [Z(90) + n(146)]$,$B = [Z(92) + n(146)]$,$C = [Z(90) + n(148)]$. Which of the following statements are incorrect?
$(a) A$ and $C$ are isotones.
$(b) A$ and $C$ are isotopes.
$(c) A$ and $B$ are isobars.
$(d) B$ and $C$ are isobars.
$(e) B$ and $C$ are isotopes.

Chemical behaviour of an atom is determined by