Question

Are atomic mass and atomic weight the same thing?

Answer 1

No, they are not the same thing.

Explanation:

An atomic weight (or relative atomic mass) is the ratio of the average mass of all the isotopes of an element to `1/12` of the mass of an atom of `""^12"C"`.

Hence an atomic weight has no dimensions.

Atomic mass is the mass of a neutral atom of a specific isotope.

The SI unit for atomic mass is the unified atomic mass unit (u), which is defined as `1/12` of the mass of an atom of `""^12"C"`.

Thus, the atomic weight of `"C"` is 12.011, but the atomic mass of `""^12"C"` is 12 u.