Organic Chemistry Study Notes

Definition: Organic chemistry is defined as the chemistry of carbon compounds.
- Carbon's unique ability: Unlike most other elements, carbon can form strong bonds with other carbon atoms as well as with a wide variety of other elements.
- Versatility of Carbon: Carbon atoms can create both chains and rings, resulting in a virtually endless diversity of molecules.
- Biological Importance: This diversity underpins life on Earth, as living organisms are primarily composed of complex organic compounds that play crucial roles in structural, chemical, and genetic functions.

The term C“organicC” originally referred to substances derived from living organisms.
- Early organic chemistry focused on natural products, including:
- Sugar
- Urea
- Starch
- Waxes
- Plant oils
Vitalism: The belief that natural products required a “vital force” for their creation, leading to the classification of organic compounds as those containing this vital force.
Inorganic Chemistry: In contrast, the study of gases, rocks, minerals, and the compounds derived from them.

A pivotal change in understanding organic chemistry occurred in the 19th century with experimental synthesis.
- Key Experiment (1828): German chemist Friedrich Wöhler successfully synthesized urea from ammonium cyanate (produced from ammonia and cyanic acid) simply by heating it in the absence of oxygen.
- This experiment challenged the notion of vitalism.

Modern organic chemistry involves studying the structures, reactions, and properties of carbon-based compounds.
Exclusions: Notably, compounds such as carbon monoxide (CO), carbon dioxide (CO₂), metal carbonates, and metal cyanides are excluded from the classification of organic compounds.

Carbon forms covalent bonds in all elemental forms and compounds.
Electron Configuration:
- The electron configuration of Carbon is:
  $1s^2 2s^2 2p^2$
Tetravalency: Carbon is tetravalent, meaning it can form four bonds.
Electronegativity: Carbon exhibits electronegativity that is intermediate between metals and nonmetals, and it prefers to share electrons.
Catenation: Carbon has the ability to bond with itself, forming stable chains, rings, and branched compounds.
- The small size of the carbon atom allows for the formation of short, strong bonds, contributing to the stability of carbon-based compounds.

Many organic compounds also contain heteroatoms, which are atoms other than carbon (C) and hydrogen (H).
- Common Heteroatoms: Most common are oxygen (O), nitrogen (N), and halogens.
- Reactivity: Most reactions in organic chemistry involve interactions between electron-rich areas of one molecule and electron-poor sites in another.
- C–C and C–H bonds are generally unreactive, while bonds between carbon and heteroatoms tend to be polar, often sites for reactions.

Five-Carbon Skeletons: Illustrations depict various arrangements of five-carbon skeletons including:
- Straight chains
- Branched chains
- Chains with double bonds
Each Carbon (C) atom can form up to four bonds with other atoms.
- Types of bonding include:
- Four single bonds
- One double bond and two single bonds
- One triple bond and one single bond
Structural Determinants: The arrangement of carbon atoms determines the skeleton configuration, where straight chains and bent chains can represent the same skeleton due to the nature of chemical bonding.

Hydrogen Atoms Attachment:
- A carbon atom single-bonded to one other atom gets three hydrogen atoms.
- A carbon atom single-bonded to two other atoms gets two hydrogen atoms.
- A carbon atom single-bonded to three other atoms gets one hydrogen atom.
- A carbon atom single-bonded to four other atoms is fully bonded (no hydrogen atoms are attached).

For double-bonded carbon atoms, they are treated as if bonded to two other atoms.
A double- and single-bonded carbon atom or a triple-bonded carbon atom is treated as bonded to three other atoms.