Atom Y Has 11 Protons, 11 Electrons, and 12 Neutrons

Question

Atom Y has 11 protons, 11 electrons, and 12 neutrons. What is the mass number of Atom Y?
A) 11
B) 12
C) 22
D) 23
E) 24

Accepted Answer

The mass number of an atom is determined by adding the number of protons and neutrons together. In this case, there are 11 protons + 12 neutrons = 23, making choice D the correct answer.