We can represent atoms by listing the number of protons, neutrons, and electrons-for example, 2p⁺, 2n⁰, 2e⁻ for helium. Which of the following represents the ¹⁸O isotope of oxygen?
A) 7p⁺, 2n⁰, 9e⁻
B) 8p⁺, 10n⁰, 8e⁻
C) 9p⁺, 9n⁰, 9e⁻
D) 10p⁺, 8n⁰, 9e⁻

Question

Quizplus · Accepted Answer

The atomic number of oxygen is 8, which means it has 8 protons. The isotope ¹⁸O indicates that there are 10 neutrons (18-8=10). Therefore, the representation would be 8p⁺, 10n⁰, Xe⁻. The number of electrons is not specified for an isotope, so it can vary. Choice B is the only option that matches this representation.

We Can Represent Atoms by Listing the Number of Protons