Question

what is mass number *
protons + electrons + neutrons
protons + neutrons
neutrons + electrons
protons + electrons
1 proton or 1 neutron weighs how many amu *
1
2
0.5
1.5

Explanation:

The mass number of an atom is the sum of the number of protons and neutrons in its nucleus. Electrons have negligible mass compared to protons and neutrons and are not included in the mass - number calculation. Protons and neutrons each have an approximate mass of 1 atomic mass unit (amu).

Answer:

1. B. protons + neutrons
2. A. 1