Which of the following species are isoelectronic: $Na, Na^+, F^-, F$?

What are the isotopes of chlorine? How do they differ from each other?

If $W$ is the mass number and $N$ is the atomic number of an element,then:

The number of protons,neutrons and electrons in the ion ${ }_{16}^{32} S^{2-}$ respectively are

$A$ monoatomic anion $(A^-)$ has $45$ neutrons and $36$ electrons. The atomic mass, group in the periodic table, and physical state at room temperature of the element $(A)$ are respectively:

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