9. Which of the following is correctly matched?
A. Gold: Element: Silver: Compound
B. Oxygen: Element: Water: Compound
C. Sugar: Element: Salt: Compound
D. Water: Element: Hydrogen: Compound
Oxygen (O2) is made up of two oxygen atoms but, just of one kind of atom oxygen (O), So it's an element. Water (H2O) is made up of two hydrogen atoms (H) and one oxygen atom (O), so it's a compound
