Final answer:
H2O. The option that represents a compound is (water), which consists of hydrogen and oxygen chemically bonded together.
Step-by-step explanation:
The student's question asks which of the given options represents a compound. A compound is a substance formed when two or more chemical elements are chemically bonded together. Looking carefully at the options and considering the charges and the number of elements:
- H2O (water) consists of hydrogen and oxygen chemically bonded, making it a compound.
- H is simply a hydrogen atom and not a compound.
- H-3 likely represents an isotope of hydrogen, which is not a compound but an atom with a specific number of neutrons.
- O-16 represents an isotope of oxygen, also not a compound but an atom with a specific number of neutrons.
Out of the given options, H2O is the correct answer, because it is composed of more than one element, hydrogen and oxygen, chemically combined in a fixed ratio.