Question

The mass number of cation 
${x}^{2 + }$
 is 40. If there are 18 electrons in the cation, the number of neutrons in the nucleus of the atom is​

Answer 1

Explanation:

we know that atomic number=proton=electron so the formula of neutron is

Mass number(A) - Atomic Number(Z)

=40-18=22 neutron is the answer