Which number is common in isotopes?

The charge on the atom containing $17$ protons,$18$ neutrons and $18$ electrons is

The spectrum of $He$ is expected to be similar to

$A$ 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 $6$:

The $^{18}O$ isotope of oxygen will have: