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Organic Chemistry - Nomenclature, conventions, and rules

__Naming organic molecules – nomenclature rules:

  1. __NO. of carbons in the longest chain containing the functional group

    1 = ==meth-

    ==2 = ==eth-

    ==3 = ==prop-

    ==4 = ==but-

    ==5 = ==pent-

    ==6 = ==hex-

    ==7 = ==hept-

    ==8 = ==oct-

    1. ==Count along the carbon chain such that the functional group has the lowest number

  2. Functional groups (a prefix or a suffix) Alkanes = -aneAlkenes = -eneHalogenoalkanes = bromo-, chloro-, etc.

    Alcohols = -anol or ==hydroxy-

    ==Nitrile = ==-onitrile

    ==Ketones = ==-anone

    ==Carboxylic acids = ==-anoic acid

    ==Esters: alcohol name first, acid name second e.g., methyl ethanoate

  3. Side/branched chains: Use NO. of carbons, + suffix “-yl”

    CH3 = ==methyl

    ==CH3CH2 = ==ethyl

    ==CH3CH2CH2 = ==propyl

  4. ==Position of functional group or side chain:

    1. The number needs to indicate which carbon the group is on.

    2. The number is placed before the functional group name.

    3. The lowest number is used if there is a choice. If more than one group: use the lowest combination of numbers.

    4. Carboxylic acids and aldehydes are always on the “first” carbon.

  5. More than one of the same things? 2 = di3 = tri==4 = tetra

  6. ==Commas and dashes: a comma is put between numbers and dashes go between numbers and words. Nothing is needed between words

__Writing Formula:

__When writing the structural formula, use brackets to show when a functional group is branched off

e.g., CH3CH(CH3)CH2CH3

  • (brackets show side-chain)

Skeletal formula: only shows the bonds between carbon atoms (looks like a stick figure)

Molecular formula: the exact amount of each atom in the molecule

Empirical formula: the simplest ratio of the amount of each atom in the molecule

__Conventions in Organic Chemistry:

__Curly arrow:

  • Movement of a single electron:

  • Movement of an electron pair: then…

__Terminology of carbon-containing functional groups:

  • __Primary carbons – carbons bonded to one other carbon

  • Secondary carbons – carbons bonded to two other carbons

  • Tertiary carbons – carbons bonded to three other carbons

  • Quaternary carbons – carbons bonded to 4 other carbons

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Organic Chemistry - Nomenclature, conventions, and rules

__Naming organic molecules – nomenclature rules:

  1. __NO. of carbons in the longest chain containing the functional group

    1 = ==meth-

    ==2 = ==eth-

    ==3 = ==prop-

    ==4 = ==but-

    ==5 = ==pent-

    ==6 = ==hex-

    ==7 = ==hept-

    ==8 = ==oct-

    1. ==Count along the carbon chain such that the functional group has the lowest number

  2. Functional groups (a prefix or a suffix) Alkanes = -aneAlkenes = -eneHalogenoalkanes = bromo-, chloro-, etc.

    Alcohols = -anol or ==hydroxy-

    ==Nitrile = ==-onitrile

    ==Ketones = ==-anone

    ==Carboxylic acids = ==-anoic acid

    ==Esters: alcohol name first, acid name second e.g., methyl ethanoate

  3. Side/branched chains: Use NO. of carbons, + suffix “-yl”

    CH3 = ==methyl

    ==CH3CH2 = ==ethyl

    ==CH3CH2CH2 = ==propyl

  4. ==Position of functional group or side chain:

    1. The number needs to indicate which carbon the group is on.

    2. The number is placed before the functional group name.

    3. The lowest number is used if there is a choice. If more than one group: use the lowest combination of numbers.

    4. Carboxylic acids and aldehydes are always on the “first” carbon.

  5. More than one of the same things? 2 = di3 = tri==4 = tetra

  6. ==Commas and dashes: a comma is put between numbers and dashes go between numbers and words. Nothing is needed between words

__Writing Formula:

__When writing the structural formula, use brackets to show when a functional group is branched off

e.g., CH3CH(CH3)CH2CH3

  • (brackets show side-chain)

Skeletal formula: only shows the bonds between carbon atoms (looks like a stick figure)

Molecular formula: the exact amount of each atom in the molecule

Empirical formula: the simplest ratio of the amount of each atom in the molecule

__Conventions in Organic Chemistry:

__Curly arrow:

  • Movement of a single electron:

  • Movement of an electron pair: then…

__Terminology of carbon-containing functional groups:

  • __Primary carbons – carbons bonded to one other carbon

  • Secondary carbons – carbons bonded to two other carbons

  • Tertiary carbons – carbons bonded to three other carbons

  • Quaternary carbons – carbons bonded to 4 other carbons

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