Setter and son confused about charged particles (4)
I believe the answer is:
ions
'charged particles' is the definition.
(I've seen this before)
'setter and son confused' is the wordplay.
'setter' becomes 'i' (the person that set the crossword).
'and' is a charade indicator (letters next to each other).
'confused' indicates an anagram.
'son' anagrammed gives 'ons'.
'i'+'ons'='IONS'
'about' acts as a link.
(Other definitions for ions that I've seen before include "N in radio comms." , "Charged atom or molecule" , "Electrically-charged particles" , "items with a charge" , "Electrically charged particles" .)