An atom of the isotope sulfur-31 consists of how many protons, neutrons, and electrons? (p = proton, n = neutron, e = electron)
A) 15 p, 16 n, 15 e
B) 16 p, 15 n, 16 e
C) 16 p, 31 n, 16 e
D) 32 p, 31 n, 32 e
E) 16 p, 16 n, 15 e

Question

Quizplus · Accepted Answer

Sulfur-31 has 16 protons (equal to its atomic number) and 15 neutrons (subtract the atomic number from the mass number). It also has 16 electrons because it is neutral and thus has equal numbers of protons and electrons. Choice A has an incorrect number of neutrons, choice C has too many neutrons and too many protons, choice D has too many protons, and choice E has an incorrect number of electrons. Therefore, the correct choice is B.

An Atom of the Isotope Sulfur-31 Consists of How Many