The Chemical Basis of Life - Vocabulary Flashcards

A set of key vocabulary flashcards derived from the BIOL 1240 lecture on atomic structure, chemical bonding, electronegativity, and molecular representations.

Element

A pure substance that cannot be further broken down.

Atom

The basic unit of matter that makes up an element, composed of protons, neutrons, and electrons.

Atomic Number

The distinct number of protons in an atom of a given element.

Mass Number

The total number of protons plus neutrons in an atom.

Isotopes

Atoms of the same element that have different numbers of neutrons.

Orbital

An area around the nucleus where electrons are most likely to be found, holding up to $2$ electrons.

Electron Shells

Grouped levels containing orbitals where electrons reside, with inner shells having lower energy and outer shells having higher energy.

Ion

An electrically charged atom that has either gained or lost an electron.

Cation

A positively charged ion formed when an atom loses an electron.

Anion

A negatively charged ion formed when an atom gains an electron.

Valence

The number of unpaired electrons in an atom's valence shell.

Valence Electrons

The electrons located in an atom's valence shell.

Valence Shell

The outermost electron shell of an atom.

Covalent Bond

A chemical bond in which two atoms share a pair of electrons.

Single Covalent Bond

A covalent bond in which two atoms share $2$ electrons (one pair).

Double Covalent Bond

A covalent bond in which two atoms share $4$ electrons (two pairs).

Triple Covalent Bond

A covalent bond in which two atoms share $6$ electrons (three pairs).

Ionic Bond

A chemical bond formed by the attraction between a cation and an anion.

Electronegativity

The tendency of an atom to attract electrons.

Nonpolar Covalent Bond

A bond in which electrons are shared equally between two atoms, resulting in a symmetrical distribution of charge.

Polar Covalent Bond

A bond in which electrons are shared unequally between atoms, resulting in partial positive and partial negative charges.

Chemical Formula

A molecular representation that simply lists the types and numbers of atoms present in a molecule.

Structural Formula

A molecular representation that shows which atoms in a molecule are bonded to each other.

Space-Filling Model

A realistic molecular representation where spheres show the true relative sizes of atoms.

Ball-and-Stick Model

A molecular representation showing the $3$-dimensional relationship between bonded atoms.

Ribbon Model

A molecular representation commonly used to highlight structural features of proteins, such as active sites.

Dry Mass

The mass remaining in cellular material after removing all water, consisting of Carbon (47\text{\null}\%), Oxygen (30\text{\null}\%), Hydrogen (9\text{\null}\%), Nitrogen (8\text{\null}\%), and other elements (6\text{\null}\%).

Organic Compounds

Chemical compounds that contain carbon bonded to other elements.