Written by the Fiveable Content Team • Last updated September 2025
Verified for the 2026 exam
Verified for the 2026 exam•Written by the Fiveable Content Team • Last updated September 2025
Definition
The atomic weight of oxygen is the weighted average mass of an atom of oxygen based on the relative abundance of different isotopes. It's approximately 16 atomic mass units (amu).
An isotope is a variant form of an element with differing numbers of neutrons but same number of protons.
Atomic Mass Unit (amu): This is a unit used to express atomic and molecular weights, equivalent to 1/12th the mass of one carbon-12 atom.
Relative Atomic Mass: This refers to the calculated weighted mean value for the masses of various isotopic atoms compared to 1/12th the mass of carbon-12.