Organic Chemistry: Carbon Hybridization Overview

Organic Chemistry

• Organic chemistry studies carbon compounds, including those used by living organisms (sugars, carbohydrates, fats).
• Carbon has six electrons, leading to an electron configuration of 1s²2s²2p².
• Carbon can form four covalent bonds, not just two as one might initially expect based on its electron configuration.
• This is due to a process called hybridization, where the shapes of the outer shell orbitals are rearranged to form more stable bonds in the resulting molecule.
• Carbon can undergo three types of hybridization depending on the reaction or molecule.

Sp³ Hybridization

• The s orbital and the three p orbitals of carbon combine to form four sp³ hybridized orbitals.
• The sp³ orbitals have a tetrahedral shape, maximizing the distance between the electrons.
• The angle between bonds is 109.15°.
• Sp³ orbitals bond through collinear overlapping (sigma bonds).

Sp² Hybridization

• The s orbital and two p orbitals of carbon atoms combine to form three sp² hybridized orbitals.
• The sp² orbitals create a trigonal planar shape.
• The angle between bonds is 120°.
• One p orbital remains unchanged (perpendicular to the sp² plane). Allows sideways overlapping(π bonds).
• Sp² hybridization forms double bonds.

Sp¹ Hybridization

• The s orbital and one p orbital of carbon combine to form two sp¹ hybridized orbitals.
• The sp¹ orbitals form linear shapes with an angle of 180 degrees between bonds.
• Two p orbitals remain unchanged, allowing for sideways overlapping(π bonds).
• Sp¹ hybridization forms triple bonds.

Homologous Series

• Homologous series are groups of structurally related compounds.
• Members differ by a -CH₂- unit.
• They show trends in physical properties when the number of carbon atoms in the series increases.
• They have a common functional group responsible for characteristic reactions and properties.

Naming Organic Compounds

• Organic compounds have common names and systematic (IUPAC) names.

• Common names lack structural information, but one compound may have more than one common name.

• Systematic names provide precise structural information.

• To name a compound, identify the longest continuous carbon chain containing the functional group.

• Number the chain starting at the end closest to the functional group, or the side branch if there are any.

• Identify and name any substituent groups.

• Write the name by combining substituent names, prefixes indicating multiple groups (di, tri etc) with the name of the parent chain and a suffix dependent on homologous series.

• Use alphabetical order when listing substituent names.

Isomerism

• Isomers have the same molecular formula but different arrangement in space.
• Structural isomers differ in the arrangement of atoms within the molecule.
• Stereoisomers have the same arrangement of atoms but differ in the spatial arrangement of those atoms. This can be:
• Chain isomers - vary in the order carbons are bonded.
• Positional isomers- differ in the location of functional groups along the same carbon chain.
• Geometric isomers- Differ in the spatial arrangement of groups around a double bond. (e.g. cis and trans).
• Optical isomers - Non-superimposable mirror images (e.g., enantiomers).
• A chiral carbon atom has four different groups attached. This creates non-superimposable mirror images (enantiomers).