Types of Chemical Bonding

What is a Chemical Bond?

A chemical bond is the force of attraction that holds atoms together in a compound. Atoms bond with one another mainly to achieve a stable electron arrangement, usually by attaining a full outer electron shell (the octet rule — eight electrons in the outermost shell, similar to noble gases).

Types of Chemical Bonds

• Ionic bonding: formed by the complete transfer of electrons from a metal atom to a non-metal atom, forming oppositely charged ions that attract each other. Example: sodium chloride (NaCl) — sodium loses an electron to become Na⁺, and chlorine gains an electron to become Cl⁻.
• Covalent bonding: formed by the sharing of electron pairs between two non-metal atoms. Example: water (H₂O), where oxygen shares electrons with two hydrogen atoms.
• Metallic bonding: found in metals, where positive metal ions are held together by a "sea" of freely moving, delocalised electrons.

Ionic Bonding in Detail

Ionic bonds typically form between a metal (which loses electrons to become a positive cation) and a non-metal (which gains electrons to become a negative anion). The resulting oppositely charged ions attract each other strongly, forming a crystal lattice structure. Ionic compounds generally have high melting points and conduct electricity when dissolved in water or molten.

Covalent Bonding in Detail

Covalent bonds form when two non-metal atoms share one or more pairs of electrons. A single covalent bond shares one pair of electrons; a double bond shares two pairs; a triple bond shares three pairs. Covalent compounds generally have lower melting points than ionic compounds and often do not conduct electricity.

Metallic Bonding in Detail

In metals, outer electrons are not held by individual atoms but move freely throughout the structure. This "sea of electrons" explains why metals conduct electricity and heat well, and why they are malleable (can be hammered into shape) and ductile (can be drawn into wires).

Why Chemical Bonding Matters

Chemical bonding explains why atoms combine to form the vast variety of substances we see around us, and why different compounds have different physical and chemical properties, such as melting point, conductivity, and hardness.