what is the item with the smallest atoms?

Question: what is the item with the smallest atoms?
- Keywords:
  atom,
  atomic,
  subatomic
Asked by landshark to Ash on 25 Jun 2012. This question was also asked by bossfish.
- Ashley Cadby answered on 25 Jun 2012:
  
  The smallest atom is Hydrogen, nearly everything has hydrogen in it. Water obviously but all plastics have hydrogen in them.

Question: what is the item with the smallest atoms?