Question

the table below gives the atomic mass and relative abundance values for the three isotopes of element m.
what is the average atomic mass (in amu) of element m?
2.86
5.36
24.30
24.98

Explanation:

Step1: Convert percentages to decimals

For the first isotope: \(78.99\%=0.7899\)
For the second isotope: \(10.00\% = 0.1000\)
For the third isotope: \(11.01\%=0.1101\)

Step2: Multiply each atomic mass by its relative - abundance (in decimal)

First product: \(0.7899\times23.9850=19.0457\)
Second product: \(0.1000\times24.9858 = 2.4986\)
Third product: \(0.1101\times25.9826=2.8607\)

Step3: Sum the products

\(19.0457+2.4986 + 2.8607=24.405\approx24.30\)

Answer:

24.30