If $A^{+}$ has $11$ protons,then the number of electrons in it is...........

The nucleus of the element having atomic number $25$ and atomic weight $55$ will contain

If the electronic configuration of a metal ion $M^{2+}$ is $2, 8, 14$ and its atomic mass is $56 \, a.m.u.$,then the number of neutrons in its nucleus is .....

Which of the following are pairs of isotopes?

Atomic number means

The nitrogen atom has $7$ protons and $7$ electrons. The nitride ion $(N^{3-})$ will have: