Question

At the center, 6 unmarked red balls are interspersed with 4 blue balls marked with plus signs. A green cloud with 2 concentric white lines surrounds the center, with 2 small green balls marked with minus signs on the inner white line and 2 small green balls marked with minus signs on the outer white line.
What value is closest to the mass of the atom?

4 amu
6 amu
10 amu
14 amu

Answer 1

Mass ≈ protons + neutrons. The nucleus has 4 protons (blue +) and 6 neutrons (red), so A = 4 + 6 = 10. Electrons add negligible mass. Answer: 10 amu.