The atomic mass of oxygen is 16. How many neutrons does oxygen have in its nucleus?

Oxygen-16 has ##8## neutrons in its nucleus.

The of a atom is comprised of the amount of neutrons and protons in its nucleus.

If the atomic mass is ##16## and there are ##8## protons in the nucleus this means that the amount of neutrons satisfies the equation ##8+N=16##, where N is the amount of neutrons. We get that ##N=8##.