The Chemical Foundation of Life

acid

molecule that donates hydrogen ions and increases the concentration of hydrogen ions in a solution

aliphatic hydrocarbon

hydrocarbon consisting of a linear chain of carbon atoms

anion

negative ion that is formed by an atom gaining one or more electrons

aromatic hydrocarbon

hydrocarbon consisting of closed rings of carbon atoms

base

molecule that donates hydroxide ions or otherwise binds excess hydrogen ions and decreases the hydrogen ions' concentration in a solution

buffer

substance that resists a change in pH by absorbing or releasing hydrogen or hydroxide ions

cation

positive ion that is formed by an atom losing one or more electrons

chemical reaction

process leading to rearranging atoms in molecules

covalent bond

type of strong bond formed between two atoms of the same or different elements; forms when electrons are shared between atoms

dissociation

release of an ion from a molecule such that the original molecule now consists of an ion and the charged remains of the original, such as when water breaks into H+ and OH-

electron

negatively charged subatomic particle that resides outside of the nucleus in the electron orbital; lacks functional mass and has a negative charge of -1 unit

electronegativity

ability of some elements to attract electrons (often of hydrogen atoms), acquiring partial negative charges in molecules and creating partial positive charges on the hydrogen atoms

functional group

group of atoms that provides or imparts a specific function to a carbon skeleton

hydrocarbon

molecule that consists only of carbon and hydrogen

hydrogen bond

weak bond between slightly positively charged hydrogen atoms and slightly negatively charged atoms in other molecules

hydrophilic

describes ions or polar molecules that interact well with other polar molecules such as water

hydrophobic

describes uncharged nonpolar molecules that do not interact well with polar molecules such as water

ion

atom or chemical group that does not contain equal numbers of protons and electrons

ionic bond

chemical bond that forms between ions with opposite charges (cations and anions)

nonpolar covalent bond

type of covalent bond that forms between atoms when electrons are shared equally between them

octet rule

rule that atoms are most stable when they hold eight electrons in their outermost shells

organic molecule

any molecule containing carbon (except carbon dioxide)

van der Waals interaction

very weak interaction between molecules due to temporary charges attracting atoms that are very close together