Related Clues:

• Energy sources
• Indivisible particles
• Fermi's particle
• Very little bit
• Tiny source of energy
• It gets smashed
• Electrons' places
• Bits in bonds
• Subject for Bohr
• Lepton site
• It's smaller than a molecule
• Bit of matter
• With 41-Down, nuclear device
• Bit to be split
• Democritus' indivisible unit