Question

if mg 2+ has 12 protons and 12 neutrons what is its atomic no and mass no

Answer 1

atomic no. is = no. of electrons = 12
and mass no. = no. of protons + no. of neutrons = 12 +12 = 24

Answer 2

Atomic number =No. of protons=no of electrons
= 12
Mass number =number of protons +number of neutrons
=12+12
=24