#AP Biology: Chemical Bonds & Macromolecules - The Night Before Review

Hey! Let's get you totally prepped for your AP Bio exam. We're going to make sure all the key concepts are crystal clear. Let's dive in!

#Chemical Bonds: The Foundation of Life

Definition: Electrons are shared between atoms. These are strong bonds that form molecules.
Single Bond: One pair of electrons shared (represented by a single line, e.g., H-H).
Double Bond: Two pairs of electrons shared (represented by a double line, e.g., O=O).
Electronegativity: An atom's pull on electrons in a bond. The bigger the difference, the more polar the bond.

Quick Fact

Remember: Covalent bonds are the backbone of organic molecules!

Examples: * Methane (CH4) * Carbon Monoxide (CO) * Iodine Monobromide (IBr)

Definition: Electrons are transferred, creating ions with opposite charges that attract each other. Forms ionic compounds (salts).
Process: One atom loses electrons (becomes positive), and another gains electrons (becomes negative).
Result: Electrostatic attraction holds the ions together.

Examples: * Sodium Chloride (NaCl) * Lithium Fluoride (LiF)

Ionic and Covalent Bonds

Image courtesy of Surfguppy.

Definition: Attraction between metal ions and a 'sea' of delocalized (free) electrons.
Properties: Explains why metals are good conductors of electricity and heat.

Examples: * Iron (Fe) * Copper (Cu) * Gold (Au)