Question

An ion M+has 10electrons & 14 neutrons what is the atomic no. &Mass no. Of M?

Answer 1

mass number = Atomic number + Number of Neutrons
= 10+14
24
Hope it helps.

Answer 2

atomic no.-20 (total no. of electron and proton present in an atom)
mass no.-24  (total no. of neutron and electron present in an atom)