One element or another returned with info (8)
I believe the answer is:
nitrogen
'one element' is the definition.
(chemical element)
'or another returned with info' is the wordplay.
'another' becomes 'tin' (I am not sure about this - if you are sure you should believe this answer much more).
'returned' says the letters should be written backwards.
'with' means one lot of letters go next to another.
'info' becomes 'gen' (informal term for information).
'or'+'tin'='ortin'
'ortin' back-to-front is 'nitro'.
'nitro'+'gen'='NITROGEN'
Can you help me to learn more?
(Other definitions for nitrogen that I've seen before include "Gas forming about four-fifths of atmosphere" , "Gas forming about four fifths of the atmosphere" , "creates much atmosphere" , "It's a gas, the strange ringtone" , "Main gas in air" .)