Which characteristic differentiates the carbon isotopes Carbon-12, Carbon-13, and Carbon-14?

Which characteristic differentiates the carbon isotopes Carbon-12, Carbon-13, and Carbon-14?

• A. Number of protons
• B. Number of neutrons
• C. Number of electrons
• D. Atomic number

Answer: (B)

Isotopes are identified by how many neutrons their nuclei contain. For carbon, the number of protons stays the same at six, which keeps the element’s identity and its atomic number fixed. The electrons in a neutral atom balance those protons, so the electron count doesn’t differentiate isotopes either. The difference shows up in the mass number, which equals protons plus neutrons. Carbon-12 has 6 neutrons (6 protons + 6 neutrons), Carbon-13 has 7 neutrons (6 + 7), and Carbon-14 has 8 neutrons (6 + 8). So the characteristic that sets these isotopes apart is the number of neutrons.

Isotopes are identified by how many neutrons their nuclei contain. For carbon, the number of protons stays the same at six, which keeps the element’s identity and its atomic number fixed. The electrons in a neutral atom balance those protons, so the electron count doesn’t differentiate isotopes either. The difference shows up in the mass number, which equals protons plus neutrons. Carbon-12 has 6 neutrons (6 protons + 6 neutrons), Carbon-13 has 7 neutrons (6 + 7), and Carbon-14 has 8 neutrons (6 + 8). So the characteristic that sets these isotopes apart is the number of neutrons.