Angriest exchange when argon was called this? (5,3)
I believe the answer is:
inert gas
'argon was called this?' is the definition.
(argon is an example)
'angriest exchange' is the wordplay.
'exchange' indicates an anagram.
'angriest' anagrammed gives 'INERT GAS'.
'when' is the link.
(Other definitions for inert gas that I've seen before include "one at the edge of a table" , "Eg, helium, xenon etc." , "He perhaps" , "He, amongst others" , "Eg, krypton or argon" .)