Link with perhaps second electron (5)
I believe the answer is:
unite
'link' is the definition.
(synonyms)
'perhaps second electron' is the wordplay.
I cannot really see how this works, but
'electron' could be 'e' (abbreviation in physics) and 'e' is present in the answer.
The remaining letters 'unit' is a valid word which might be clued in a way I don't see.
This may be the basis of clue (or it may be nonsense).
'with' is the link.
Can you help me to learn more?
(Other definitions for unite that I've seen before include "Bring together, become one" , "Come together as allies or comrades" , "Get together" , "Join together, become allies" , "Couple" .)