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Lewis structure
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representations of molecular structure
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Lewis structure

Also known as: Lewis formula
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representations of molecular structure
representations of molecular structure Several methods of representing a molecule's structure. In Lewis structures, element symbols represent atoms, and dots represent electrons surrounding them. A pair of shared electrons (covalent bond) may also be shown as a single dash. The ball-and-stick model better illustrates the spatial arrangement of the atoms. For aromatic compounds, the Kekulé structure is common, in which each bond is represented by a dash, carbon atoms are implied where two or more lines meet, and hydrogen atoms are usually omitted. Bond-line formulas, similar to the Kekulé structure, are often used for complex nonaromatic organic compounds. Sugars are often drawn as Fischer projections, in which the carbon “backbone” is drawn as a straight vertical line, with carbon atoms implied where horizontal lines intersect the vertical one.

A Lewis structure is a diagram that shows the bonding between atoms of a molecule and the lone pairs of electrons that may exist in the molecule. Lewis introduced the convention of representing valence electrons as dots around an element's symbol. These dots can be transferred between symbols to illustrate bond formation.

Covalent bonds, typically formed between nonmetals, involve shared electron pairs. In a Lewis structure, a shared electron pair between two atoms is represented by a line, signifying a covalent bond. Additional electron pairs not involved in bonding are called lone pairs. The octet rule, a key concept in Lewis structures, suggests that atoms tend to gain, lose, or share electrons to achieve a full outer shell of eight valence electrons, thereby minimizing energy. This principle helps explain the stability of molecules.

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3 Britannica Sources
  1. chemical bonding - Lewis formulation of a covalent bond
  2. chemical bonding - Resonance
  3. chemical bonding - Molecules with multiple bonds

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