Molybdenum has an atomic number of 42.Several common isotopes exist,with mass numbers of 92,94,95,96,97,98,and 100.Therefore,which of the following is true?

Question

Quizplus · Accepted Answer

The mass number of an atom is equal to the sum of its protons and neutrons. Since molybdenum has an atomic number of 42 (meaning it has 42 protons), the isotopes listed have between 50 and 58 neutrons, as the mass number of each isotope is 92, 94, 95, 96, 97, 98, and 100, respectively. Therefore, choice A is correct. Choice B is incorrect because the number of valence electrons is determined by the number of electrons in the outermost energy level, which does not change between isotopes of the same element. Choice C is incorrect because the number of protons is equal to the atomic number and does not vary within a given element. Choice D is incorrect because the number of electrons in a neutral atom is equal to the number of protons, which does not vary within a given element.

Molybdenum Has an Atomic Number of 42