Final answer:
A stable molecule has less energy than the individual atoms because atoms form chemical bonds to achieve a stable electron configuration, which is lower in energy and is more stable. The formation of a stable molecule releases energy and does not change the mass significantly compared to its atoms.
Step-by-step explanation:
The claim about why atoms bond to form stable molecules that is best supported by Sasha's model is that a stable molecule has less energy than the individual atoms. Atoms form chemical bonds with other atoms to achieve a stable electron configuration, which is energetically favorable. This state of lower energy is more stable and less likely to undergo a chemical reaction. Molecular stability is linked to the energy required to break a chemical bond; thus, the formation of a stable molecule releases energy, making it lower in energy than its constituent atoms. Furthermore, although there is a mass defect in nuclear reactions, this concept does not apply to chemical bonding in molecules where mass is conserved.
Chemical bonds, such as covalent bonds, exist to hold atoms together in a molecule, and the strength of these bonds is measured by the energy necessary to break them. Stronger bonds require more energy to break, indicating that a stable molecule is at a lower energy state. In contrast, the mass of a molecule does not increase or decrease significantly compared to the sum of the masses of the individual atoms as they are conserved during chemical reactions.