Question

nitrogen-15 contains ____ protons, __ neutrons, and ____ electrons.

a. 7, 8, 7
b. 7, 7, 7
c. 7, 8, 8
d. 8, 7, 7

Explanation:

Step1: Recall atomic number of nitrogen

Nitrogen has an atomic number of 7. The atomic number is equal to the number of protons and in a neutral atom, the number of electrons. So, number of protons = 7 and number of electrons = 7.

Step2: Calculate number of neutrons

The mass - number of Nitrogen - 15 is 15. Mass number = number of protons+number of neutrons. So, number of neutrons = mass number - number of protons = 15 - 7=8.

Answer:

A. 7, 8, 7