Question

illustrated here are three different ____ of carbon. they vary by the number of ____. a ions; neutrons b ions; electrons c molecules; protons d isotopes; neutrons

Explanation:

Isotopes are atoms of the same element with the same number of protons (atomic number) but different numbers of neutrons (and thus different mass numbers). The three forms (\(^{12}\text{C}\), \(^{13}\text{C}\), \(^{14}\text{C}\)) have the same number of protons (6, since carbon has atomic number 6) but different numbers of neutrons (6, 7, 8 respectively). Ions involve electron gain/loss, molecules are groups of atoms, so options A, B, C are incorrect.

Answer:

D. Isotopes; neutrons