# Based on the data table below, which shows three isotopes of neon, what is a correct numerical setup for calculating the average atomic mass of neon?

Feb 2, 2017

The quoted atomic mass is the weighted average of the individual isotopes. I get $20.74 \cdot \text{amu}$.
{90.9%xx19.99+0.3%xx20.99+8.8%xx21.99}*g*mol^-1=20.74*"amu".