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-

Verified step by step guidance

1. Identify the atomic number of oxygen, which is 8. This number represents the number of protons in an oxygen atom.
2. Understand that the number of electrons in a neutral atom equals the number of protons. Therefore, an oxygen atom also has 8 electrons.
3. Recognize that the notation 18O refers to an isotope of oxygen where the total number of protons and neutrons equals 18. Since there are 8 protons in oxygen, subtract 8 from 18 to find the number of neutrons: 18 - 8 = 10 neutrons.
4. Review the options given and find which one correctly lists 8 protons, 10 neutrons, and 8 electrons. This matches the description of the 18O isotope.
5. Select option b. 8p+,10n0,8e− as it correctly represents the 18O isotope of oxygen with 8 protons, 10 neutrons, and 8 electrons.

Key Concepts

Atomic Structure

Atoms consist of protons, neutrons, and electrons. Protons are positively charged and found in the nucleus, neutrons are neutral and also located in the nucleus, while electrons are negatively charged and orbit the nucleus. The number of protons defines the element, while the number of neutrons can vary, leading to different isotopes of the same element.

Isotopes

Isotopes are variants of a particular chemical element that have the same number of protons but different numbers of neutrons. This difference in neutron count results in varying atomic masses. For example, oxygen has several isotopes, including 16O, 17O, and 18O, with 18O having two more neutrons than the most common isotope, 16O.

Notation of Isotopes

Isotopes are often represented using a notation that includes the element symbol and the mass number, which is the sum of protons and neutrons. For instance, 18O indicates an oxygen atom with 8 protons and 10 neutrons (8 + 10 = 18). Understanding this notation is crucial for identifying isotopes and their properties in various contexts.