Which of the following is the smallest unit of matter that can take part in a chemical reaction?
Atom
Explanation for the correct option(s):
D. Atom
Explanation for the incorrect option(s):
A: Molecule
A molecule is made up of atoms.
B: Element
Element is made up of atoms of the same kind.
C: Compound
A compound is formed by a chemical reaction.
Hence, option D is correct.