Question

If an element has 20 protons and 20 neutrons in the nucleus of its atoms , what is the mass number of the atom?

Answer 1

A=z+n

A=20+20

A=40

Step-by-step explanation:

Not sure if I'm correct but I was taught that mass number is calculated by A=z+n where A is the mass number, z is the proton number and n is the number of neutrons.