This is a writing exercise for the student, and answers will vary. Sample question: Which of the following always contains more than one type of atom? a. element b. molecule c. compound d. none of these The answer is "compound". Elements are composed of one type of atom (isotopes may be present, but do not have to be). Molecules can consist of covalently bonded identical atoms. Compounds, by definition, are composed of different elements that are bonded together.