In the atomic model, what keeps its properties during a chemical reaction?

In the atomic model, atoms are the fundamental building blocks of matter that retain their identity and properties during a chemical reaction. When a chemical reaction occurs, the way atoms are arranged may change, but the atoms themselves do not change into different types of atoms. This means that the chemical properties associated with those specific atoms remain unchanged. For instance, a carbon atom will always exhibit properties characteristic of carbon, regardless of whether it is part of carbon dioxide, hydrocarbons, or another compound.

While molecules, substances, and elements have their own significance in chemistry, the question specifically focuses on the atomic level. Molecules can change during a reaction, as they are composed of atoms bonded together, and specific substances can alter their properties when they undergo reactions. Elements refer to pure substances that consist of only one type of atom, but the most precise answer in the context of chemical reactions is indeed atoms themselves, as they are the smallest entities that maintain their identity and characteristics.