Ch. 25 Carbon and Its Compounds 25-1: The Element Carbon

Importance of Carbon  Carbon forms the backbone of nearly every molecule living organisms make or use.

Allotropes of Carbon  allotropes: forms of the same element that have different bonding patterns or arrangements  Diamond: Each carbon atom bonds to 4 other carbon atoms. Extremely strong and hard bonds (hardest natural substance on Earth) Uses: jewelry, coat some surfaces, cutting tool

Allotropes of Carbon  Graphite: Carbon atoms arranged in sheets or layers, held together by weak attractive forces Soft, comes off in sheets Uses: pencil “lead”, lubrication (graphite spray)

Allotropes of Carbon  Amorphous carbon: No predictable arrangement Produced when carbon compounds decompose Ex: charcoal, soot, bone black

Allotropes of Carbon  Fullerenes: “Buckyballs” Soccer ball shaped arrangement of carbon, consisting of alternating pentagons and hexagons. Named for Buckminster Fuller, architect (see pg. 807). Uses: medical research (AIDS), storage of hazardous materials

Unique Bonding of Carbon  Smallest atom that is halfway filled with valence electrons  Forms exactly four short, strong, covalent bonds (can be single, double or triple covalent)

Unique Bonding of Carbon  Forms long chain molecules (sugars, DNA, proteins, carbohydrates) {remember, it acts a backbone for molecules}  Why is carbon not diatomic?  It would have to have a quadruple bond, which is too unstable to exist.