Molybdenum has an atomic number of 42. Several common isotopes exist, with mass numbers from 92-100. Which of the following can be true?
A) Molybdenum atoms can have between 50 and 58 neutrons.
B) Molybdenum atoms can have between 50 and 58 protons.
C) Molybdenum atoms can have between 50 and 58 electrons.
D) Isotopes of molybdenum have different numbers of electrons.

Question

Quizplus · Accepted Answer

Molybdenum has an atomic number of 42, which means it has 42 protons in its nucleus. The different isotopes of molybdenum have mass numbers ranging from 92-100, which corresponds to the number of protons plus neutrons in the nucleus. Therefore, the number of neutrons in molybdenum isotopes can range from 50 (mass number 92-42=50) to 58 (mass number 100-42=58). Protons and electrons, on the other hand, are normally identical in number in electrically neutral atoms. Therefore, B and C are not correct choices. D is also not correct as isotopes only differ in the number of neutrons, not electrons.

Molybdenum Has an Atomic Number of 42