Question

The table below gives the atomic mass and relative abundance values for the three isotopes of element M.

Answer 1

The average atomic mass formula is:

$average atomic mass = \Sigma (percent abundane)\times (atomic mass)$

Substituting the values in the formula:

$average atomic mass = \frac{78.99\times 23.9850+10\times 24.9858+11.01\times 25.9826}{100}$

$average atomic mass = \frac{1894.57515+249.858+286.068426}{100}$

$average atomic mass = 24.30516 amu$

Hence, $24.30516 amu$ is the average atomic mass of element M.