Nitrogen-14 has 7 protons. How many neutrons does it have?

7

Explanation:

Using information found on the Periodic Table of Elements:

Nitrogen contains 7 protons, 7 neutrons, and 7 electrons.

...

Atomic number is 7

Atomic mass is 14

The mass number is the sum of protons and neutrons in the nucleus.

=> You can subtract the atomic number from the mass number to find the number of neutrons.