D
Element cannot be broken down into simpler substances by chemical methods. Hence (iv) is correct
Only option D has (iv)

Thank you! I chose D too but answer key states C :( Assuming D is correct, do you know if options ii or iii is right or wrong for an element? Thank you!

yea.. I guess both r possible also.
Metals r an example. Grp 1 metal like sodium react with oxygen to form sodium oxide. Sodium also reacts vigorously with cold water to form sodium hydroxide and hydrogen.
I guess 2 and 3 r better cause in an experiment point of view, u can observe the change to conclude that its an element. While 4 is true, u cannot cfm as there r compounds that don't decompose on normal heating like sodium carbonate
Guess this qn is testing on metals

Thank you Miss Tan! :)