When a compound is broken down in the chemical reaction, its atoms are used to form new compound.
Answer: Option A
Explanation:
In a chemical reaction involving one or more compounds, the atoms in the compounds breaks and bombardment happens to create a new compound. The chemical formula of the new compound comes form its parent compound due to mixing of molecules.
Hence Option B is invalid as atoms are not destroyed to create a new molecule. All chemical reactions are not exothermic hence option C is invalid.
