Solution: Which of the following formulas refers to a pure element?(A) H2O(B) H2O2(C) O2(D) Xf(E) answer to both (C) and (D)

Problem

Which of the following formulas refers to a pure element?

(A) H2O

(B) H2O2

(C) O2

(D) Xf

(E) answer to both (C) and (D)