The two stable isotopes of carbon present in naturally occurring carbon are

The number of electrons,protons and neutrons in a species are equal to $18$,$16$ and $16$ respectively. Assign the proper symbol to the species.

Which of the following does not contain a number of neutrons equal to that of $_{18}^{40}Ar$?

The group having isoelectronic species is:

When a sulphur atom becomes a sulphide ion,

Two atoms of elements $X$ and $Y$ are isotones of each other. Their mass numbers are $70$ and $72$ respectively. If the atomic number of $X$ is $34$,then the atomic number of $Y$ is ..........