Question

Where does most of the mass of an atom come from? What parts of the atom make it up?

Answer 1

nucleus

Step-by-step explanation:

The majority of an atoms' mass comes from the protons and neutrons that make up its nucleus. Electrons are the least massive of an atom's constituent particles, with a mass of 9.11 x 10-31 kg and a size too small to be measured by current techniques.