What is the average atomic mass of gold if half of the gold found in nature has a mass of 197 amu and half has a mass of 198 amu?

Nov 28, 2015

$\text{Average mass} = 197.5 a . m . u .$

Explanation:

The average atomic mass can be calculated by:

"Average mass"=sum("isotope mass")xx("percent abundance")

If half of gold is found in nature with a mass of $197 a . m . u .$ therefore its percent abundance is 50% and the percent abundance of the isotope ""^198Au is also 50%.

"Average mass"=(197xx(50%)/(100%))+(198xx(50%)/(100%))=197.5a.m.u.