What is the number of protons and neutrons in a nucleus.

Answer 1

Atomic number = number of protons

Number of neutrons = mass number - number of protons

So Carbon has atomic number 6, so always has 6 protons in the nucleus

There are isotopes of carbon with mass numbers 14, 12.

So carbon-12 has 6 protons, 6 neutrons, carbon 14 has 6 protons, 8 neutrons

Mike