How do atoms combine to form chemical compounds?

Atoms combine to form chemical compounds primarily through the interaction of their valence electrons, which are the electrons in the outermost shell. These interactions allow atoms to achieve more stable electron configurations, often resembling the eight-electron arrangement of noble gases, known as the octet rule.12

There are three primary ways atoms form bonds:

• Ionic Bonding: One atom transfers electrons to another, creating oppositely charged ions. The resulting electrostatic force of attraction locks these ions together into a compound, such as sodium chloride.34
• Covalent Bonding: Atoms share pairs of electrons. In the valence-bond model, these electrons are treated as being shared between nuclei, while molecular-orbital theory describes them as occupying orbitals that encompass the bonded atoms.34
• Metallic Bonding: In metals, atoms release outer electrons that form a shared "sea" of electrons, which holds the positive ions together.3

Additionally, atoms and molecules can interact through weaker forces, such as hydrogen bonds or van der Waals forces, which do not involve the direct exchange or sharing of electrons in the same manner as primary chemical bonds.3