A student observes a model of two bonded atoms. She is told that both atoms are nonmetals. Which of the following is a valid conclusion?
A. The student is looking at a model of atoms held together by a covalent bond.
B. The student is looking at a model of a metalloid.
C. The student is looking at a model of a crystal lattice.
D. The student is looking at a model of atoms held together by an ionic bond.