Question

Nate and Vic are trying to determine the atomic mass of the atom shown below. Nate thinks it has an atomic mass of 11 u, while Vic thinks it has an atomic mass of 6 u. Who is correct and why?

A. Nate is correct. An isotope’s atomic mass is based on the number of protons and neutrons in the nucleus.

B. Vic is correct. An isotope’s atomic mass is based on the number of electrons in the electron cloud.

C. Vic is correct. An isotope’s atomic mass is based on the number of protons in the nucleus.

D. Neither is correct. The atomic mass is based on the number of neutrons in the nucleus. This isotope’s atomic mass is 5 u.

Answer 1

Answer: A is correct. I don't see the "element shown below," but it isn't needed to answer this question.

Explanation: By definition, the atomic mass is based on the sum of protons (1 AMU each) and neutrons (1 AMU each). Electrons are assigned a value of 0 AMU.