Element and compounds.

Today in science class I learned that a element has only one type of atom and a compound is when 2 or more elements chemically combined. The 2 elements we used was magnesium and oxygen that that created Magnesium oxide but when we created magnesium oxide we cannot turn it back into 2 separate elements. We then used a bunsen burner and used tongs to hold the magnesium and then hovered it over the bunsen burner and then it caught fire. It turned into a white flame and burned for at least 3-4 seconds and then went out. Magnesium oxide is a white solid powder which when burned makes a cool white solid flame.