Organic Chemistry: 1.2 Organic Chem / Carbon Atom

Organic Chemistry

The study of carbon-based compounds, which are fundamental to all living organisms. Generally contains hydrogen, and sometimes oxygen, nitrogen, sulfur and other elements.

Jöns Jacob Berzelius

A Swedish chemist known for his work in organic chemistry and for introducing chemical symbols. The term Organic Chemistry was first coined in 1806.

How many valence electrons does a carbon atom have?

Four valence electrons that allows it to form four covalent bonds to other atoms.

Resonance

A way to describe molecules where electrons are not fixed in one place but can move or "spread out" across several atoms. This helps make the molecule more stable. In aromatic compounds, resonance leads to delocalization of electrons, reducing energy and increasing stability.

Catenation

The ability of carbon atoms to form long chains or rings by bonding to themselves, which is fundamental to the structure of organic compounds.

Bond Strength and Stability

Organic compounds typically feature strong covalent bonds, particularly carbon-carbon (C-C) and carbon-hydrogen (C-H) bonds, which are stronger than ionic bonds found in inorganic compounds. Covalent bonds result in stable structures, while ionic bonds may be more brittle and dependent on the presence of solvent for stability.

Isomerism

Carbon’s ability to form various structural arrangements leads to isomerism, where compounds with the same molecular formula can have different structures and properties.

Hybridization

The concept of mixing atomic orbitals to create new hybrid orbitals for bonding, allowing carbon to form various shapes and structures in organic compounds. This property allows carbon to form linear (sp), trigonal planar (sp²), and tetrahedral (sp³) geometries, further expanding its versatility in bonding.

Carbon-based Structure

Organic compounds are primarily composed of carbon, often bonded to hydrogen, oxygen, nitrogen, and other non-metals.

Covalent Bonding

Organic compounds are characterized by covalent bonds, where atoms share electrons rather than transferring them as in ionic bonds.

Low Melting and Boiling Points

Most organic compounds have relatively low melting and boiling points compared to inorganic compounds, particularly because of the weaker intermolecular forces like Van Der Waals interactions or hydrogen bonds.

Solubility

Organic compounds tend to be soluble in non-polar solvents like benzene or chloroform, but many are insoluble in water. However, compounds with polar groups (e.g., alcohols, carboxylic acids) can dissolve in water.

Combustibility

Organic compounds are generally combustible, reacting with oxygen to produce carbon dioxide, water, and heat.

Diverse Structures and Sizes

Organic compounds can range from simple molecules like methane to large, complex polymers such as proteins, carbohydrates, and synthetic plastics.

Hydroxyl group (-OH)

Found in alcohols.

Carbonyl group (C=O)

Found in aldehydes and ketones.

Carboxyl group (-COOH)

Found in carboxylic acids.

Amino group (-NH2)

Found in amines and amino acids.

Alkanes

Saturated hydrocarbons with single bonds (e.g., methane, ethane).

Alkenes

Unsaturated hydrocarbons with at least one double bond (e.g., ethene, propene).

Alkynes

Unsaturated hydrocarbons with at least one triple bond (e.g., ethyne, propyne).

Aromatic Hydrocarbons

Compounds that contain a benzene ring (e.g., benzene, toluene).

Structural Isomerism

Differences in the arrangement of atoms.

Stereoisomerism

Differences in the spatial arrangement of atoms, including enantiomers and diastereomers.

Substitution Reactions

One atom or group of atoms is replaced by another (common in alkanes and aromatics).

Addition Reactions

Atoms or groups are added to a double or triple bond (common in alkenes and alkynes).

Elimination Reactions

Atoms or groups are removed, typically leading to the formation of double or triple bonds.

Oxidation-Reduction (Redox) Reactions

Organic compounds can undergo redox reactions where electrons are transferred, particularly involving oxygen or hydrogen atoms.