Atomic number and mass number of ordinary atoms, using helium as an example. The atomic number (Z) is also the number of protons (np). The Mass number (A) is the total number of neutrons and protons.
Contributor: Peter Hermes Furian
ID : 520186266
 is also the number of protons (np). The Mass number (A) is the total number of neutrons and protons.')){kind=link}