Chemistry (school) · Part 03
Bonding and structure
How atoms join, and why that decides what a substance is like.
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- IonAn atom or group of atoms that has gained or lost electrons, so it carries an electrical charge. Losing electrons makes a positive ion. Gaining them makes a negative ion.
- Ionic bondThe strong attraction between a positive ion and a negative ion. It forms when a metal gives electrons to a non-metal.
- Covalent bondA bond made when two atoms share a pair of electrons. It forms between non-metal atoms.
- Metallic bondingThe attraction between positive metal ions and a sea of free electrons that move between them. It holds metal atoms together.
- Ionic latticeThe regular, repeating 3D pattern of positive and negative ions in an ionic compound. Every ion is surrounded by ions of opposite charge.
- Simple moleculeA small group of atoms joined by covalent bonds. The forces between molecules are weak, so these substances melt and boil easily.
- Giant covalent structureA huge network of atoms joined by strong covalent bonds. These substances have very high melting points.
- AllotropeA different form of the same element, with its atoms arranged in a different pattern. The pattern changes the properties.
- AlloyA mixture of a metal with another element, usually another metal. Alloys are often harder than pure metals.