Carbon and Hydrocarbons

Overview

This lesson covers the unique properties of the carbon atom, the types of bonds it forms, and the classification and naming of hydrocarbons.

Unique Properties of Carbon

• Carbon is found in all living things and some non-living things like coal and diamond.
• Carbon atoms can bond with hydrogen, oxygen, nitrogen, and halogens to form complex organic compounds.
• Organic compounds contain carbon and typically have low thermal stability and weaker covalent bonds.
• Carbon can form long chains and rings due to its bonding abilities.

Chemical Bonding and Structures

• Carbon's ground state electron configuration is 1s² 2s² 2p² with four valence electrons.
• Hydrogen has a configuration of 1s¹, contributing one valence electron.
• Covalent bonds involve sharing electrons between atoms rather than losing or gaining them.
• A Lewis dot structure represents valence electrons as dots around an atom.
• The octet rule states atoms are stable with eight electrons in their valence shell.
• Sigma (σ) bonds are formed by head-on overlap of orbitals; pi (π) bonds are formed by sideways overlap of p orbitals.

Hydrocarbons: Types and Formulas

• Hydrocarbons are organic compounds made of only carbon and hydrogen.
• Saturated hydrocarbons (alkanes) have only single bonds, general formula CnH2n+2.
• Unsaturated hydrocarbons include:
  • Alkenes: contain double bonds, general formula CnH2n.
  • Alkynes: contain triple bonds, general formula CnH2n-2.
• Physical and chemical properties depend on hydrocarbon structure.

Naming Hydrocarbons

• IUPAC rules require identifying bond type, saturation, and carbon count.
• Alkanes have names ending in "-ane" (saturated).
• Alkenes have names ending in "-ene" (double bonds).
• Alkynes have names ending in "-yne" (triple bonds).
• The name prefix depends on the number of carbon atoms (e.g., eth-, prop-, but-).

Examples and Applications

• Ethane (C2H6): an alkane with two carbons.
• Propene (C3H6): an alkene with three carbons and one double bond.
• Butyne (C4H6): an alkyne with four carbons and one triple bond.
• Butane is used in LPG and various industrial applications.
• Propene is used in welding and metalwork.
• Ethyne is used in oxyacetylene torches.

Key Terms & Definitions

• Organic compound — compound containing carbon bonded to hydrogen, oxygen, nitrogen, or halogens.
• Covalent bond — chemical bond formed by sharing electron pairs between atoms.
• Hydrocarbon — compound made only of carbon and hydrogen.
• Alkane — saturated hydrocarbon with only single bonds.
• Alkene — unsaturated hydrocarbon with at least one double bond.
• Alkyne — unsaturated hydrocarbon with at least one triple bond.
• Lewis dot structure — diagram representing valence electrons as dots around an element.
• Sigma bond (σ) — bond formed by head-on orbital overlap.
• Pi bond (π) — bond formed by sideways overlap of p orbitals.

Action Items / Next Steps

• Review and study the table of hydrocarbon names and structures in the lesson.
• Prepare for the next lesson on general classes and uses of organic compounds.