Atomic magnitudes

Atomic magnitudes

1. The atomic mass unit is the UMA.

   • The atomic number of a chemical element is the total number of protons each atom of that element has. It is represented by the letter Z.

2. The mass number: is the number of protons plus the number of neutrons that the atom has. It is represented by the letter A and is placed as a superscript to the left of the element symbol.