General Chemistry/Overview of bonding
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[edit] Introduction to Bonding
Put simply, chemical bonds join atoms together to form more complex structures (like molecules or crystals). Bonds can form between atoms of the same element, or between atoms of different elements. There are several types of chemical bonds which have different properties and give rise to different structures.
In general, atoms try to react to form valence shells containing eight electrons. The octet rule describes this.
Ionic bonds form between positive ions (cations) and negative ions (anions). In an ionic solid, the ions arrange themselves into a rigid crystal lattice. NaCl (common salt) is an example of an ionic substance.
Covalent bonds are formed when the orbitals of two (non-metal) atoms physically overlap and share electrons with each other. This gives rise to two structures: molecules and covalent network solids. Methane (CH4) and water (H2O) are examples of covalently bonded molecules, and glass is a covalent network solid.
Metallic bonds occur between metal atoms. In a metallically bonded substance, the atoms' outer electrons are able to freely move around - they are delocalised to form an 'electron pool'. Iron is a metallically bonded substance.
Chemical bonding is one of the most crucial concepts in the study of Chemistry. In fact, the properties of materials are basically defined by the type and number of atoms they contain and how they are bonded together.
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