A chemical reaction is a process where some substances change into new substances because their atoms are rearranged into new combinations.

The substances involved

  • The starting substances are called reactants.
  • The new substances formed are called products.
  • In a reaction, reactants are converted into products, often written in a word or symbol equation like:
    reactants → products.

What happens to the atoms

  • The atoms themselves are not created or destroyed; they are just rearranged in new ways. The same atoms that are in the reactants end up in the products.
  • During a chemical reaction, chemical bonds between atoms in the reactants are broken, and new bonds form to make the products.
  • Because the atoms are connected differently after the reaction, the products have different properties from the reactants.

In simple terms

You start with certain substances (reactants), their atoms get rearranged as old bonds break and new ones form, and you end up with different substances (products), while the total number and types of atoms stay the same.