Question

The total number of neutrons in dipositive zinc ions with mass number 70 is?

Answer 1

Atomic number (Z) = 30

Mass number (A) = 70

So,

No. Of neutrons = A - Z

= 70 - 30

= 40 neutrons.

Also, pro tip, the charge on an atom doesn't affects the number of neutrons at all!! ( 'cause charge indicates how many 'electrons' are lost by the atom right?)

Answer 2

The total number of neutrons in dipositive zinc ions with mass number 70 is?

=> 70 - 30

=> 40 neutrons