Question

the isotope oxygen - 18 has an atomic number of 8. which of the following shows the correct number of protons, electrons, and neutrons, respectively, in a neutral oxygen - 18 atom?
a 8 protons, 8 electrons, 10 neutrons
b 8 protons, 8 electrons, 8 neutrons
c 8 protons, 10 electrons, 8 neutrons
d 8 protons, 10 electrons, 10 neutrons

Explanation:

Step1: Recall atomic number property

The atomic number is equal to the number of protons. Given atomic number of oxygen - 18 is 8, so number of protons = 8.

Step2: Determine number of electrons in neutral atom

In a neutral atom, the number of electrons is equal to the number of protons. So number of electrons = 8.

Step3: Calculate number of neutrons

The mass number of oxygen - 18 is 18. Mass number = number of protons+number of neutrons. So number of neutrons = mass number - number of protons = 18 - 8=10.

Answer:

A. 8 protons, 8 electrons, 10 neutrons