Chemistry help plz!! I took Chem. 2 yrs ago, don't remember much from it. Next yr, I'm planning to take AP Chem. so I have to do Summer HW. I know that H is the symbol of Hydrogen, C is Carbon.Can someone plz help me how to figure out how to write element symbol, for example how to write element symbol of hydrocarbon? Or is there a website that can help me remember how to write an element SYMBOL when you know the name of the element and vice versa. Thank you very much.