The atomic weight of an element is $39$. The number of neutrons in its nucleus is one more than the number of protons. The number of protons,neutrons,and electrons respectively in its atom would be

An isotope of oxygen has a mass number of $18$. Other isotopes of oxygen will have the same:

State whether the following statements are true or false:
$(i)$ Isobars have different atomic numbers.
$(ii)$ $_{14}^{30}\text{Si}$,$_{16}^{32}\text{S}$ are isotones.
$(iii)$ Niels Bohr was the first to suggest that the atom is spherical.
$(iv)$ Rutherford's model is accepted as the nuclear model of the atom.

Which of the following species are isoelectronic species? $(i)$ $O^{2-}$, $(ii)$ $F^{-}$, $(iii)$ $Na^{+}$, $(iv)$ $Mg^{2+}$

The expression $Ze$ gives :

Identify the isoelectronic pair from the following.