Possible Clues:

• General name for a proton or neutron
• Part of an atom of gas probed by London university
• Particle of inert gas probed by English university
• Both kings out of joint regarding very small thing
• Eccentric uncle working to find subatomic particle
• Particle identified by Greek character, an Athenian demagogue
• Egyptian queen embraced by sister? That’s a very little matter
• Queen briefly embraced by sister, a tiny thing
• London university splitting noble gas particle
• Particle discovered in London college in gas