Question #7359c

1 Answer
Jul 17, 2014

Thanks for your excellent question.

From all the models I have seen, atoms are basically round.

And, yes, they do come in different sizes. The sizes of atoms depend on two factors:

a: how many protons are in the nucleus. Across a period, atoms actually become smaller as you go from the left of a period to the right in the same period. That is because you are adding protons (which are pulling on the oppositely charged electrons). An example of this is that one atom of lithium is much larger than one atom of neon (they are in the same period).

b: The number of energy levels of electrons you have also help determine the size of the atom. The more energy levels (shells) you have, the larger the atom. An example of this: one atom of sodium is smaller than one atom of rubidium.

Hope this helps!!