Atomic mass does not include ________ in its calculation. The atomic number of an element is the number of ___________.

Question

Quizplus · Accepted Answer

The atomic mass of an element is the average sum of the protons and neutrons in a group of those atoms. However, electrons are so much smaller (have so much less mass) than protons and neutrons that they don't factor into the calculation. So, the atomic mass is the sum of the masses of protons and neutrons.
The number of protons in the nucleus is the defining property of an element, and is referred to as the atomic number.

Atomic Mass Does Not Include ________ in Its Calculation