Answer:
average atomic mass = 207.2172085 amu
Step-by-step explanation:
To get the average atomic mass of an element using the abundance of its isotopes, all you have to do is multiply each isotope by its percentage of abundance and then sum up all the products.
For the question, we have:
203.97304 amu has an abundance of 1.390% (0.0139)
205.97447 amu has an abundance of 24.11% (0.2411)
206.97590 amu has an abundance of 22.09% (0.2209)
207.97665 amu has an abundance of 52.41 % (0.5241)
The average atomic mass can be calculated as follows:
average atomic mass = 203.97304(0.0139) + 205.97447(0.2411)
+ 206.97590(0.2209) + 207.97665(0.5241)
average atomic mass = 207.2172085 amu
Hope this helps :)