In nature, oxygen has three common isotopes. The atomic masses and relative abundances of these isotopes are given in the table below. Isotope Atomic Mass (amu) Relative Abundance O-16 15.995 99.759% O-17 16.995 0.037% O-18 17.999 0.204% Calculate the average atomic mass of oxygen. Show all of your calculations below.

The average atomic mass of oxygen is 15.999 amu

Explanation:

Mass of isotope O-16 = 15.995 amu

% abundance of isotope O-16= 99.759 % =

Mass of isotope O-17 = 16.995 amu

% abundance of isotope O-17 = 0.037% =

Mass of isotope O-18 = 17.999 amu

% abundance of isotope O-18 = 0.204% =

Formula used for average atomic mass of an element :

Thus the average atomic mass of oxygen is 15.999 amu