During a chemical reaction, atoms of one element are neither created nor destroyed; they undergo rearrangement to form new compounds. The reaction involves the breaking and forming of chemical bonds between atoms. The law of conservation of mass dictates that the total mass of the reactants must equal the total mass of the products, emphasizing that atoms remain conserved. The rearrangement of atoms results in the formation of different molecules or compounds while maintaining the same number and types of atoms. This fundamental principle ensures the preservation of matter at the atomic level in chemical processes.