BIO: Polarity and Water

Ionic Bonds

Atoms transfer electrons to each other, creating oppositely charged ions that attract each other

Nonpolar covalent

Electrons are shared equally, and there is no charge (neutral)

Polar covalent

Unequal sharing of electrons between atoms creates partial positive and negative charges of opposite ends of the molecule

Adhesion

Water molecules to form hydrogen bonds with other molecules and “cling” to surfaces

Cohesion

Water molecules forming hydrogen bonds with each other

Surface tension

The tendency of water molecules to resist external force due to cohesive forces between them, creating a skin on the surface

Capillary action

The ability of water to flow in narrow spaces against gravity (like veins in plants), due to cohesion and adhesion.

Evaporative cooling

Heat energy must be transferred and absorbed to break hydrogen bonds between water molecules and cause evaporation; when water evaporates, it creates a cooling effect