James Kepley, age 10, of Staten Island, New York, for his question

Are atoms bigger than molecules?

A molecule is a package of one or more atoms. But the 90 or so everyday atoms come in various sizes, ranging from midgets to giants. The smallest atom is hydrogen and the smallest molecule is a package of two hydrogen atoms. Naturally this molecule is bigger than a single atom of hydrogen. But it is smaller than some of the riant atoms.

Each atori is made from tinier particles of matter. Some have more particles than others. For example, the hydrogen atom has only two particles and the uranium has hundreds. An atom with many particles weighs more than one with only a few and usually it is bigger. Naturally a molecule is bigger than any one of its own atoms. But a uranium atom is bigger than a molecule of two hydrogen atoms. So some molecules are bigger than certain atoms and some atoms are bigger than certain molecules.