Question

what is atomic no. and mass no???

Answer 1

Atomic number is the number of protons (or electrons) in a neutral atom.

Mass number is the number of nucleons in an atom, ie, the number of protons plus the number of neutrons.

Answer 2

mass no. is = no. of proton + no of next (promto = eletron)

atomic no is areagement of elements accouring to their neutrons only