ISOTOPE PENNIUM LAB

Complete the following to calculate the average atomic mass for the pennium atom and make a hard copy

1. Get total weight for all atoms.(click and drag to total the click on summation symbol)
2. Split the weights into the columns provided for heavy and light isotopes and get total as in one
3. Get averages for each isotope by doing = click on box for totals divide by number of atoms in the column
4. Calculate abundance for both isotopesby click on box enter = click on isotope total/click on total weight then enter
5. Calculate the average atomic mass by (click on ave wt Heavy isotope * abundance) + (click on ave wt Light isotope * abundance) enter

Answer these questions on your original lab paper and attach your calculations above to it.

1. Why is the atomic mass number for an element not whole numbers?

2. Why would you think the atomic mass would be whole numbers?

3. Why can’t you just add the two averages of the isotopes together and divide by two to get the overall average of the atomic weight of the element pennium? Or asked this way. Why do you have to multiply by abundance instead of just averaging the two averages of the isotopes together?