Which statement best defines an atom?

Which statement best defines an atom?

• A. The smallest unit of matter
• B. A type of molecule
• C. A chemical compound
• D. A bond between atoms

Answer: (A)

An atom is the smallest unit of matter that still has the properties of its element. It’s the basic building block from which everything is made, and atoms can join with other atoms to form molecules. A molecule, by contrast, is a group of two or more atoms bonded together, so calling an atom a molecule isn’t correct. A chemical compound is a substance made from two or more elements in a fixed ratio, which is a larger concept than an individual atom. A bond is the force that holds atoms together in a molecule or other structure, not the unit itself. So the statement describing the atom as the smallest unit of matter best captures what an atom is.

An atom is the smallest unit of matter that still has the properties of its element. It’s the basic building block from which everything is made, and atoms can join with other atoms to form molecules. A molecule, by contrast, is a group of two or more atoms bonded together, so calling an atom a molecule isn’t correct. A chemical compound is a substance made from two or more elements in a fixed ratio, which is a larger concept than an individual atom. A bond is the force that holds atoms together in a molecule or other structure, not the unit itself. So the statement describing the atom as the smallest unit of matter best captures what an atom is.