scientifically accurate elemental battlegrounds

most of these "elemental" fighting games are inaccurate. water isn't even an element!!! its a compound! thats acceptable i guess. but tell me, wth is the "nightmare" element!?!?! how is that remotely close to an element???? this game has ACTUAL elements: hydrogen, helium, copper, uranium, etc im not trying to be a chemistry nerd it was just a shower thought disclaimer: very very very incomplete game