Two atoms have the same atomic mass but different atomic numbers. Such atoms are called as:

The nitride ion in lithium nitride is composed of:

Among the following,the set of isoelectronic ions is:

Identify the isobars and isotopes from the following: $_6^{14}C, _6^{13}C, _7^{14}N, _6^{12}C$

Positive ions are formed from the neutral atom by the

Which one of the following sets of ions represents a collection of isoelectronic species? (Given: Atomic Number: $F: 9, Cl: 17, Na: 11, Mg: 12, Al: 13, K: 19, Ca: 20, Sc: 21$)