Isotopes were discovered by

Positive ions are formed from the neutral atom by the

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

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.

The introduction of a neutron into the nuclear composition of an atom would lead to a change in

Which of the following elements is isoelectronic with $Na^{+}$?