# How would you determine the atomic weight of an atom?

Dec 16, 2015

It depends on how you define it.

If you're a chemist, then you would normally take "atomic weight" and "atomic mass" to just be "atomic mass". If you're a physicist, you probably would cringe at equating the two, because weight is in $\text{N}$, not $\text{g}$.

I'll answer this from the physicist's perspective.

Atomic mass is just written directly on the periodic table. It's the one that has a lot of decimal places. So hydrogen's atomic mass is $\textcolor{b l u e}{\text{1.00794 g/mol}}$.

Atomic weight, then, would be $\text{W = mg}$.

$\text{W} = \left(1.00794\right) \left(9.80665\right)$
$\textcolor{b l u e}{\text{= 9.88451 N/mol}}$