The atomic number of an atom reveals the number of ________.
A) electrons in the atomic nucleus
B) protons in the atomic nucleus
C) protons plus neutrons
D) protons plus electrons
E) neutrons plus electrons

Question

Quizplus · Accepted Answer

The atomic number of an atom is equal to the number of protons in the atomic nucleus. This is the defining characteristic of an element and is used to determine its placement on the periodic table. The number of electrons in an atom is equal to the number of protons, assuming the atom is electrically neutral, but this is not revealed by the atomic number itself. The total number of protons plus neutrons is known as the atomic mass, which can vary even within a single element. Therefore, answer choices C, D, and E are not correct.

The Atomic Number of an Atom Reveals the Number of ________