Question

part iii: calculate the average atomic mass for the following isotopes. 1) neon has two isotopes: ne - 20 with an abundance of 91% and ne - 22 with an abundance of 9% 2) an unknown element “x” has two isotopes: x - 56 with an abundance of 60% and x - 58 with an abundance of 40%

Explanation:

Step1: Convert percentages to decimals

For Ne - 20, the abundance as a decimal is $0.91$, and for Ne - 22, it is $0.09$.

Step2: Calculate average atomic mass of neon

The average atomic mass $A_{Ne}$ is calculated as $A_{Ne}=20\times0.91 + 22\times0.09=18.2+1.98 = 20.18$.

Step3: Convert percentages to decimals for element X

For X - 56, the abundance as a decimal is $0.6$, and for X - 58, it is $0.4$.

Step4: Calculate average atomic mass of element X

The average atomic mass $A_{X}$ is calculated as $A_{X}=56\times0.6+58\times0.4 = 33.6+23.2=56.8$.

Answer:

1. The average atomic mass of neon is $20.18$.
2. The average atomic mass of element X is $56.8$.