Ch2 BIO1200 Basic Chemistry

Element

A pure substance made of one kind of atom.

Atom

The smallest functional unit of matter that contains all the properties of the element.

Proton

A positively charged subatomic particle found in the nucleus of an atom.

Neutron

A subatomic particle with no charge, found in the nucleus of an atom.

Electron

A negatively charged subatomic particle that orbits the nucleus of an atom.

Ionic Bond

A bond formed between a positively charged ion and a negatively charged ion.

Covalent Bond

A bond formed when two atoms share electrons.

Polar Molecule

A molecule that has a partial positive charge on one end and a partial negative charge on the other due to unequal sharing of electrons.

Hydrophilic Molecules

Molecules that dissolve in water; they are usually charged or polar.

Hydrophobic Molecules

Molecules that cannot dissolve in water; they are usually nonpolar and uncharged.

Amphipathic Molecule

A molecule that has one polar/charged end and one nonpolar/hydrophobic end.

Acid

A substance that releases H+ ions when it dissolves in water.

Base

A substance that releases OH- ions when it dissolves in water.

pH Scale

A measure of how acidic or basic a substance is, expressed as the negative logarithm of the H+ concentration.

Electronegativity

The ability of an atom to attract or gain electrons.

Cohesion

The attraction between water molecules due to hydrogen bonding.

Adhesion

The attraction of water molecules to charged surfaces.

Ions

Atoms that have gained or lost electrons, resulting in a charge.