I deliver iodine? I’m not sure - it’s some kind of element (7)
I believe the answer is:
iridium
'some kind of element' is the definition.
'i deliver iodine? i'm not sure' is the wordplay.
'deliver' becomes 'rid' (to rid from is to free or deliver from).
'iodine?' becomes 'I' (chemical symbol).
'i'm not sure' becomes 'um' (expression of hesitation).
'i'+'rid'+'i'+'um'='IRIDIUM'
'it's' acts as a link.
(Other definitions for iridium that I've seen before include "Hard silvery metal" , "Hard metal element, Ir" , "number 77" , "Hard metallic element" , "Silvery-white metal" .)