# Magnesium has three naturally occurring isotopes with masses of 23.99 amu, 24.99 amu, and 25.98 amu and natural abundances of 78.99%, 10.00% and 11.01% respectively. How do you calculate the atomic mass of magnesium?

##### 1 Answer
Sep 12, 2016

Approx. $24.3 \text{ amu}$.

#### Explanation:

The atomic mass is the weighted average of the individual isotopic masses:

(23.99xx78.99%+24.99xx10.00%+25.98xx11.01%)*g=24.31*g

I have given you answer in $g$ which here is equivalent to $\text{amu}$.