Atomic Mass is essentially a measure of the average of the different isotopes of a specific element. Therefore while some periodic tables round to cool round numbers they are not exactly exact as in all the combinations with that number of protons its a very slim probobilty they would round out to a round number. Oxygen for instance on my periodic table is listed as 15.999. So I would say exact is not the word for it.
Yes, but I did say to round the number in the description so that it would make more sense. If not for that, then I wouldn't be able to make this quiz.
What do you suggest I change 'exact' to?