Question

Oxygen has an atomic mass of 16 and an atomic number of 8. how many neutrons are present

Answer 1

An atoms atomic mass is the sum of it's proton and neutrons found in the nucleus. An atom's atomic number is the number of protons an atom has. By subtracting an element's atomic number from the atomic mass you can calculate the number of neutrons. For oxygen it would be sixteen minus eight, so oxygen has eight neutrons.