Related Clues:

• Teeny bit
• Source of nuclear energy
• Play by Euripides
• Nuclear energy source
• Smallest amount
• Kind of exchange
• Electrically charged particle
• It's attractive
• With 60-Across, 1960's TV cartoon hero
• K+, e.g.
• Smashing subject
• Unit of a molecule
• It carries a small charge
• Basic building block
• Wee thing