Bio 151: The Chemical Context of Life Flashcards

Vocabulary flashcards covering core concepts of introductory biology regarding elements, subatomic particles, bonding, electronegativity, and chemical reactions based on Dr. Huynh's Bio 151 lecture.

Matter

Anything that takes up space and has mass; it is composed of elements and compounds.

Element

A substance that cannot be broken down to other substances by chemical reactions.

Compound

A substance consisting of two or more elements in a fixed ratio.

Trace Elements

Elements required by the human body in quantities accounting for less than $0.01\%$ of body mass.

Atom

The smallest unit of an element, comprised of smaller subatomic particles.

Proton

A subatomic particle located in the nucleus with a positive charge and a mass of approximately $1\,\text{Da}$.

Neutron

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

Electron

A subatomic particle located in a cloud of negative charge surrounding the nucleus, possessing a negative charge and a mass of approximately $0.0005\,\text{Da}$.

Atomic Number

The number of protons in an atom's nucleus, which also equals the number of electrons in pure, neutral elements.

Mass Number

The sum of protons plus neutrons in an atom's nucleus.

Atomic Mass

An atom's total mass, which is approximated by its mass number.

Isotopes

Two atoms of the same element that differ in their number of neutrons.

Radioactive Isotopes

Isotopes that decay spontaneously, giving off particles and energy.

Valence Electrons

Electrons located in the outermost shell of an atom.

Covalent Bond

A chemical bond formed by the sharing of a pair of valence electrons.

Single Bond

A covalent bond involving the sharing of one pair of valence electrons.

Double Bond

A covalent bond involving the sharing of two pairs of valence electrons.

Molecule

Two or more atoms held together by covalent bonds, representing the smallest unit of a compound.

Electronegativity

An atom's attraction for shared electrons in a bond.

Nonpolar Covalent Bond

A covalent bond where atoms share electrons equally.

Polar Covalent Bond

A covalent bond where one atom is more electronegative, causing unequal sharing of electrons and partial charges.

Ion

A charged atom or molecule.

Cation

A positively charged ion.

Anion

A negatively charged ion.

Ionic Bond

A chemical bond formed by the electrostatic attraction between oppositely charged ions.

Ionic Compound (Salt)

A compound formed by ionic bonds.

Intramolecular Bond

A chemical bond formed within a single molecule.

Intermolecular Bond

A weaker, often temporary interaction formed between separate molecules.

Hydrogen Bond

An intermolecular bond formed when a hydrogen atom covalently bonded to one electronegative atom is also attracted to another electronegative atom.

Chemical Reactions

Processes that involve the making and breaking of chemical bonds.

Reactants

The starting molecules of a chemical reaction.

Products

The final molecules of a chemical reaction.

Chemical Equilibrium

The state reached when the rates of the forward reaction equal the rates of the reverse reaction.