In a chemical reaction, what is the main change that occurs among atoms?

In a chemical reaction, the primary change that occurs among atoms is that they exchange or share electrons. This process is fundamental to the formation of chemical bonds, which can be ionic or covalent in nature. In ionic bonding, atoms transfer electrons to achieve a full outer shell, leading to the formation of charged ions that attract each other. In covalent bonding, atoms share electrons to fill their outer electron shells, resulting in more stable configurations.

The exchange or sharing of electrons allows atoms to bond with one another, which alters the arrangement of atoms and creates new substances. These interactions are what ultimately define the chemistry of a reaction and lead to the transformation of the initial reactants into products with different properties.

This understanding of electron interactions is crucial in grasping concepts related to molecular formation and the behavior of substances during reactions, making it clear why this choice accurately describes the primary change that occurs among atoms during chemical reactions.