Are atomic mass and atomic weight the same thing?

1 Answer
Jan 15, 2016

Answer:

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.