The atomic number of the isotope ²³⁸U of uranium is 92.The nucleus of this isotope contains:
A) 92 protons and 146 neutrons.
B) 92 protons, 54 neutrons, and 92 electrons.
C) 184 protons, 92 electrons, and 54 neutrons.
D) 146 protons and 92 neutrons.

Question

Quizplus · Accepted Answer

The atomic number of an element is equal to the number of protons in its nucleus. In this case, the atomic number of uranium is 92, so there are 92 protons in the nucleus of this isotope. The mass number of an element is equal to the total number of protons and neutrons in its nucleus. The mass number of ²³⁸U is 238, so the number of neutrons is 238 - 92 = 146. Therefore, the correct answer is A, as it states that the nucleus of this isotope contains 92 protons and 146 neutrons.

The Atomic Number of the Isotope ²³⁸U of Uranium Is