BIOL112 Chemical Bonds, Acids + Bases

Atom

Basic unit of matter with protons and electrons.

Nucleus

Core of an atom containing protons and neutrons.

Electron Cloud

Region around nucleus containing electrons.

Mass Number

Total of protons and neutrons in an atom.

Atomic Number

Number of protons in an atom.

Valence Electrons

Electrons in outermost shell influencing bonding.

Orbitals

Sub-rows in electron configuration holding electrons.

Covalent Bond

Chemical bond formed by shared electron pairs.

Hydrogen Bond

Weak bond between polar molecules involving hydrogen.

Polarity

Distribution of electrical charge across a molecule.

Nonpolar Molecule

Electrons shared equally between atoms.

Polar Molecule

Unequal sharing of electrons creates partial charges.

Electronegativity

Atom's ability to attract electrons in a bond.

Hydrophilic

Substances that dissolve easily in water.

Hydrophobic

Substances that do not dissolve in water.

Hydrophobic Interaction

Nonpolar molecules aggregate to minimize water disruption.

Van der Waals Force

Weak attraction between nonpolar molecules due to dipoles.

Ionic Bond

Electrostatic attraction between oppositely charged ions.

Cation

Positively charged ion formed by electron loss.

Anion

Negatively charged ion formed by electron gain.

Mole

Unit measuring amount of substance in chemistry.

Molarity

Concentration of a solution in moles per liter.

Acid

Substance that releases H+ ions in solution.

Weak Acid

Partially dissociates in solution, important in biology.

Base

Substance that accepts H+ ions in solution.

Weak Base

Partially accepts protons, important in biology.

Titration Curve

Graph showing pH change as titrant is added.

Conjugate Base

Formed from an acid after losing a proton.

Equivalence Point

Point in titration where acid is fully converted.

Buffer

Resists pH changes by neutralizing added acids or bases.

Functional Groups

Specific groups of atoms that determine molecular properties.