Question

| The table below gives the atomic mass and relative abundance values for the three isotopes of eleme

Answer 1

To calculate the average atomic weight, each exact atomic weight is multiplied by its percent abundance, then add the results together and round off to an appropriate number of significant figures. So according to what’s given, the average atomic mass of elements M should be (23.9850 x 0.7899) + (24.9858 x 0.1000) + (25.9826 x 0.1101) = 24.30

Answer 2

Answer:

The average atomic mass is 24.30 amu.

Explanation:

When there are at least 2 isotopes for an atom, each with its own atomic mass, we can calculate an average atomic mass (AAM), which considers the mass of each isotope and its relative abundance. The mathematical expression is:

$AAM=\frac{\Sigma m_{i} \times ab_{i} }{\%100}$

where,

AAM is the average atomic mass

mi is the mass of each isotope

abi is the relative abundance of each isotope

If we replace this expression with the data we have, then:

$AAM=\frac{23.9850amu \times 78.99 \% + 24.9858amu \times 10.00\% + 25.9826amu \times 11.01 \%}{100\%} =24.30amu$