How many neutrons protons and electrons make up an atom of nitrogen-15?
Nitrogen has seven protons. Anything with seven protons within its nucleus (and only seven) is an atom of nitrogen. The mass number (15) is the sum of the protons and neutrons. 15 – 7 = 8 neutrons. The number of electrons matches the number of protons, except in ions (charged atoms). So for neutral monatomic nitrogen (nitrogen typically bonds with itself forming N2) there would be seven electrons.
