was the popup telling you what they were not working, the colours were arbitrary. There's a popup when you get close
Not sure if there was even a popup i'll have to try again and see, but i went in the square as a hydrogen molecule so maybe this wasn't what needed to go in the battery.
Oh i see for the colors ! Well i thought there was like some convention on "this atom is always represented using this color etc..." so at first i thought how am i gonna identify anything with that dumb brain of mine XD