Bio Test 1

Polar Covalent Bond

A covalent bond where electrons are shared unequally between atoms.

Polar Molecule

A molecule with an uneven distribution of charge, creating positive and negative ends.

Cohesion

Attraction between molecules of the same substance.

Adhesion

Attraction between molecules of different substances.

Thermal Energy

The total kinetic energy of all particles in a substance

Heat

Thermal energy transferred from a warmer object to a cooler object

Temperature

A measure of the average kinetic energy of particles in a substance

Evaporative Cooling

Cooling that occurs when the fastest-moving molecules evaporate from a liquid

Solution

A homogeneous mixture in which one substance is dissolved in another

Solvent

The substance that does the dissolving in a solution

Solute

The substance that is dissolved in a solution

Aqueous Solution

A solution in which water is the solvent

Hydrophilic

Having an attraction to water; "water-loving”

Acid

A substance that increases the hydrogen ion (H⁺) concentration of a solution

Base

A substance that decreases the hydrogen ion (H⁺) concentration of a solution

Buffer

A substance that resists changes in pH by accepting or releasing H⁺ ions

Element

A pure substance made of only one type of atom

Compound

A substance made of two or more different elements chemically combined

Atom

The smallest unit of an element that retains its properties

Neutron

A subatomic particle with no charge found in the nucleus

Proton

A positively charged subatomic particle found in the nucleus

Electron

A negatively charged subatomic particle found outside the nucleus

Atomic Nucleus

The dense center of an atom containing protons and neutrons

Atomic Number

The number of protons in an atom's nucleus

Mass Number

The total number of protons and neutrons in an atom

Atomic Mass

The weighted average mass of an element's naturally occurring isotopes

Isotope

An atom of an element with a different number of neutrons

Electron Shells

Energy levels around the nucleus where electrons are found

Valence Electrons

Electrons in the outermost shell of an atom

Valence Shell

The outermost electron shell of an atom

Orbital

A region around the nucleus where an electron is most likely to be found

Covalent Bond

A chemical bond formed by sharing electrons

Molecule

Two or more atoms held together by covalent bonds

Single Bond

A covalent bond formed by sharing one pair of electrons

Double Bond

A covalent bond formed by sharing two pairs of electrons

Valence

The bonding capacity of an atom, determined by its valence electrons

Electronegativity

An atom's ability to attract shared electrons in a bond

Nonpolar Covalent Bond

A covalent bond where electrons are shared equally

Ion

An atom or molecule with a net electric charge due to gaining or losing electrons

Cation

A positively charged ion that has lost electrons

Anion

A negatively charged ion that has gained electrons

Ionic Bond

A bond formed by the attraction between oppositely charged ions

Hydrogen Bond

A weak attraction between a partially positive hydrogen atom and a partially negative atom in another molecule