[Download the accompanying PDF worksheet.]
Calculate the Average Atomic Mass
- Calculate the average atomic mass of an element with two naturally occurring isotopes: 85X (72.15%, 84.9118 amu) and 87X (27.85%, 86.9092 amu). What is this element?
- Chromium has the following isotopic masses and relative abundances. Calculate the average atomic mass of chromium to two decimal places.
| Mass Number | Iostopic Mass (amu) | Percent Abundance |
| 50 | 49.9461 | 4.35% |
| 52 | 51.9405 | 83.79% |
| 53 | 52.9407 | 9.50% |
| 54 | 53.9389 | 2.36% |
[Want more practice problems? Check out Atomic Mass Practice Problems Part II.]
