Pion

6 clues
Subatomic bit
Atomic particle
Nuclear particle
Subatomic particle
Unstable nuclear particle
Unstable subatomic particle
Similar answers:
&tongued
1piece
3ona
Aaabonds
Aabond
Aagonizes
Aalon
Aaron
Aaronbirdie
Aaronbirth
Aaronburr
Aaronburrconspiracy
Aaronburro
Aaronburrow
Aaroncabotlodge
Aaroncarter
Aaroncopland
Aarondirtylaundry
Aaroneckhart
Aaronhall