Chemistry
Chemical Bonding
Quick fact
The strongest chemical bond is the triple bond in nitrogen gas (N₂), requiring over 900 kJ/mol of energy to break—this is why nitrogen is so unreactive.
Why this is interesting
You are made of trillions of atoms, but what holds them together to form your body, the air you breathe, and the ground beneath your feet? The answer lies in chemical bonds—the invisible forces that glue atoms into everything.
Read the full explanation
Understanding Chemical Bonding
Imagine atoms as tiny magnets: some have a strong pull for extra electrons, while others want to give electrons away. Chemical bonding happens when atoms transfer electrons (like one atom ‘donating’ an electron to another) or share electrons (like two friends holding the same baseball). These arrangements satisfy each atom’s desire to fill its outer electron shell, a stable state called the octet rule. Ionic bonds form between metals and nonmetals through electron transfer, creating charged ions that attract each other. Covalent bonds form between nonmetals when atoms share pairs of electrons. Metallic bonds occur in metals, where free electrons flow around a lattice of positive ions, allowing conductivity and malleability.
A deeper explanation
At the heart of chemical bonding is the interplay between electrostatic forces and quantum mechanics. Atoms have a nucleus of protons (positive) surrounded by electrons (negative). When atoms come close, the attractive force between one atom’s nucleus and another’s electrons overcomes the repulsion between the positive nuclei. The result is a net glue that holds them together. The type of bond is determined by the difference in electronegativity—how strongly an atom attracts shared electrons. A large difference (1.7) leads to ionic bonding; a small or zero difference (0–0.4) to nonpolar covalent; intermediate values create polar covalent bonds. Bond energy, the strength of the bond, directly influences a substance’s melting point, hardness, and reactivity. This explains why diamonds (covalent network) are extremely hard and why salt (ionic) has a high melting point. Understanding bonding allows chemists to predict how substances interact, design new materials, and explain life’s chemistry—for example, the hydrogen bonds that hold DNA strands together.