1 mole of oxygen 6. The difference between the neutron number and the atomic number is known as the neutron. Oxygen Is An Element Which Has The Atomic Number Of 8 And Its Symbol Is O Oxygen Save Earth Ocean Plants Neutron 16 8 8. . One atomic mass unit is equal to 166 x 10 -24 grams. Copy Sheet of paper on top of another sheet. The unit of measure for mass is the atomic mass unit amu. However this atomic mass is the average atomic mass of all the isotopes in nature. That being said the most common. The mass of 6. Mass numbers of typical isotopes of Oxygen are 16. However this atomic mass is the average atomic mass of all the isotopes in nature. The total number of neutrons in the nucleus of an atom is called the neutron number of the atom and is given the symbol N. So when most of us refer to oxygen it is the oxygen with 8 neutrons. Therefore an oxygen atom has eight. 022 10 23 molecules o...