Chapter 2: Biological Chemistry Intro

Matter

Anything that has mass and occupies space

Atom

The smallest functional unit of an element that has the chemical properties of the element; all matter is composed of this

Molecules

Two or more atoms bonded together

Element

A pure substance composed of only one kind of atom

Proton

A positively charged particle found in the nucleus of an atom. The number of these in an atom is called the atomic number and defines each type of element

Neutron

An uncharged particle found in the nucleus of an atom

Electron

A negatively charged particle found in the orbitals around an atomic nucleus

Atomic Nucleus

The center of an atom (contains protons and neutrons)

Orbital

The region surrounding the nucleus of an atom where the probability is high of finding a particular electron

Electron Shell

A region around an atom’s nucleus where electrons reside (large atoms have more of these than smaller atoms)

Energy

The ability to do work or cause change

Valence Electron

An electron in the outermost shell of an atom that is available to share with other atoms. These allow atoms to form chemical bonds with each other

Atomic Number

The number of protons in an atom

Atomic Mass

An atom’s mass relative to the mass of other atoms. For example, the most common form of carbon, which has six protons and six neutrons, and has a ______ of 12

Dalton (Da)

A measure of atomic mass. One of these equals one-twelfth the mass of a carbon atom

Mole

The amount of any substance that contains the same number of particles as there are atoms in exactly 12 g of carbon

Isotope

A form of an element that contains a different number of neutrons from the element’s others of these

Radioisotopes

An isotope found in nature that is inherently unstable and usually does not exist for long periods of time. These decay and emit energy in the form of radiation

Mineral Element

A chemical element other than oxygen, hydrogen, carbon, and nitrogen that is required for life and present in significant amounts in living organisms

Trace Element

An element that is essential for the normal growth and function of living organisms but is required in extremely large quantities