Chapter 2: Biochemistry, Atoms, Ions, and Molecules

Vocabulary flashcards covering chemical elements, atomic structure, isotopes, radioactivity, and ionic properties based on Chapter 2 lecture notes.

Biochemistry

The study of the molecules that compose living organisms, including carbohydrates, fats, proteins, and nucleic acids.

Chemical Element

The simplest form of matter to have unique chemical properties.

Atomic Number

The number of protons in the nucleus of an atom, used to identify each chemical element.

Trace Elements

Elements present in minute amounts in the body that play vital roles.

Minerals

Inorganic elements extracted from soil by plants and passed up the food chain to humans, making up $4\%$ of body weight.

Atom

The smallest unit of matter, derived from a Greek term meaning 'indivisible'.

Planetary Model

Model of atomic structure proposed by Neils Bohr in $1913$ that is useful as a schematic, but not an accurate structure.

Nucleus

The center of an atom, composed of protons and neutrons.

Proton

A subatomic particle in the nucleus with a single $(+)$ charge and a mass of $1\text{ amu}$.

Neutron

A subatomic particle in the nucleus with no charge and a mass of $1\text{ amu}$.

Electron

A subatomic particle with a single $(-)$ charge and very low mass, located in concentric clouds surrounding the nucleus.

Atomic Mass

A value approximately equal to the total number of protons and neutrons in an atom.

Valence Electrons

Electrons in the outermost shell of an atom that determine its chemical bonding properties.

Isotopes

Varieties of an element that differ only in the number of neutrons and therefore in atomic mass.

Atomic Weight

The relative atomic mass of an element accounting for the fact that an element is a mixture of isotopes.

Radioisotopes

Unstable isotopes that decay and give off radiation.

Radioactivity

The process in which unstable isotopes decay and give off radiation.

Madame Curie

The first woman to receive a Nobel Prize ($1903$) and PhD; coined radioactivity, discovered polonium and radium, and pioneered radiation therapy.

Ion

A charged particle (atom or molecule) with an unequal number of protons and electrons.

Ionization

The transfer of electrons from one atom to another.

Anion

A particle that has a net negative charge due to the gain of electrons.

Cation

A particle that has a net positive charge due to the loss of electrons.

Salts

Electrically neutral compounds of cations and anions that readily dissociate in water into ions and act as electrolytes.