In nature, atoms are almost never found as independent particles. Most atoms exist in combinations bonded together by ionic, covalent, or metallic bonds. Atoms that are bonded together have less potential energy than when they are independent particles, making them more stable.
Ionic bonds are bonds that form between metals and nonmetals due to the attraction between anions and cations.
Compounds with ionic bonds are characterized by powdery or granulated appearance, solubility, high melting point, and electrical conductivity in a liquid or dissolved state.
Covalent Bonds (polar and nonpolar)
Covalent bonds are formed between nonmetals from the sharing of electron pairs. In nonpolar covalent bonds, electrons are shared equally, and the charge is distributed evenly. In polar covalent bonds, electrons sharing and charge distribution is unequal.
Compounds with covalent bonds are characterized by powdery or granulated appearance, solubility in most polar bonds, low melting point, and no electrical conductivity in any state.
Metallic bonds form between metals due to the attraction between atoms and the surrounding sea of electrons. In metals, vacant orbitals in the outer energy levels overlap, allowing electrons to roam freely about the metal. These mobile electrons are delocalized, meaning they do not belong to any single atom.
Compounds with metallic bonds are characterized by shiny appearance, insolubility, high melting point, and conductivity in any state.