What is the mass of oxygen-16?

Answer 1

If you really meant to ask "What is the mass defect of oxygen-16," this is how you do it.

mass defect = # of protons x mass of one proton + # of neutrons x mass of one neutron - mass of the nucleus

The atomic number of oxygen-16 is 8, so there are 8 protons. The mass of one proton is approximately 1.0073 amu. The Atomic Mass of oxygen-16 is 16, so there are 8 neutrons in oxygen-16. (Atomic mass of 16 minus atomic number of 8 = # of neutrons in oxygen-16.) The mass of one neutron is approximately 1.0087 amu. The mass of the nucleus of oxygen is 16.

Now substitute the values into the "mass defect" equation:

mass defect = 8x1.0073+8x1.0087-16=approximately 0.128 amu.

Answer 2

Atomic mass and atomic weight are different. Atomic mass refers to the mass of an individual atom of a particular isotope. The atomic mass is, therefore, the total mass of nutons, protons and also electrons(though negligible) of one single isoptope of the element.Whereas, the atomic weight is a weighted mean of ratio atomic masses of the isotopes of an element to the 1/12 of atomic mass of carbon-12, the weights being their natural abundance of the isopes in a planet or a given situation. The natural abundance may vary from planet to planet.But at a particular time in a planet the atomic weight remains constant and may vary slightly over time.

Oxygen has several isotopes. But the most stanble isotopes and their atomic masses are as below:

Isotopes Protons Nutrons Atomic mass Aundance fraction

16O 8 8 16 0.99757

17O 8 9 17 0.00038

18O 8 10 18 0.00205

Therefore, The atomic weight of oxygen is

(16*(0.99757)+17*(0.00038)+18*(0.00205)/(1/12 of atomic mass of carbon12) = 16.00448 .

Again, the atomic mass of an isotope is a whole number as there is no fractional protons or nutrons are there.

Answer 3

Not all, but most. Oxygen can exist as O-16, O-17, or O-18. All three isotopes are stable, although most oxygen atoms have an atomic mass of 16.