If the electronic configuration of a metal ion $M^{2+}$ is $2, 8, 14$ and its atomic mass is $56 \, a.m.u.$,then the number of neutrons in its nucleus is .....

Provide the symbol,name,atomic number $(Z)$,mass number $(A)$,and the number of electrons $(e)$,protons $(p)$,and neutrons $(n)$ for elements with atomic numbers $1$ to $10$.

Which of the following is not isoelectronic with $O^{2-}$?

The number of electrons plus neutrons in ${}_{19}^{40} K^{+}$ is $.....$

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

Which of the following pairs are isoelectronic species?