Find the number of neutrons,electrons,and protons in the following species:
$(i)$ $_{15}^{31}P$
$(ii)$ $_{11}^{23}Na^{+}$
$(iii)$ $_{16}^{32}S^{2-}$
$(iv)$ $_{101}^{235}X$
$(v)$ $_{20}^{40}Ca^{2+}$
$(vi)$ $_9^{19}F^{-}$

(N/A) The number of protons is equal to the atomic number $(Z)$.
The number of neutrons is equal to the mass number $(A)$ minus the atomic number $(Z)$,i.e.,$n = A - Z$.
The number of electrons is equal to the atomic number $(Z)$ minus the charge on the species.

Species	Protons $(p)$,Electrons $(e^-)$,Neutrons $(n)$
$(i) \ _{15}^{31}P$	$p=15, e^-=15, n=16$
$(ii) \ _{11}^{23}Na^{+}$	$p=11, e^-=10, n=12$
$(iii) \ _{16}^{32}S^{2-}$	$p=16, e^-=18, n=16$
$(iv) \ _{101}^{235}X$	$p=101, e^-=101, n=134$
$(v) \ _{20}^{40}Ca^{2+}$	$p=20, e^-=18, n=20$
$(vi) \ _9^{19}F^{-}$	$p=9, e^-=10, n=10$