Chemistry of Life + Fluids & Electrolytes

Vocabulary flashcards covering core concepts in introductory chemistry, atomic structure, chemical bonding, solutions, and acid-base homeostasis for BIOL 2001C.

Atom

The smallest unit of matter that retains the properties of a particular element and cannot be broken down further by normal chemical means.

Proton ($\text{p}^+$)

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

Neutron ($\text{n}^0$)

A subatomic particle located in the nucleus with a charge of $0$ and a mass of $1\,\text{amu}$.

Electron ($\text{e}^-$)

A subatomic particle located in the electron cloud/shells with a charge of $-1$ and a mass of $\sim 0\,\text{amu}$.

Nucleus

The overall positively charged central region of an atom containing protons and neutrons, housing most of the atom's mass.

Electron cloud

The negatively charged three-dimensional region of shells surrounding the nucleus containing electrons with almost no mass.

Neutral atom

An atom containing an equal number of protons and electrons, resulting in no net electrical charge.

Valence electrons

The electrons in the outermost electron shell that determine how atoms interact and form chemical bonds.

Atomic number

The specific number of protons contained within the nucleus of an atom.

Mass number

The total number of protons plus neutrons for one specific isotope of an atom.

Atomic mass (Atomic weight)

The weighted average mass of all naturally occurring isotopes of an element.

Isotope

Atoms of the same element that have the same number of protons but different numbers of neutrons.

Mole

A standard scientific unit representing $6.022 \times 10^{23}$ particles of a substance.

COHN

An acronym for Carbon, Oxygen, Hydrogen, and Nitrogen, which together compose approximately $95-96\%$ of living body composition.

Molecule

A structure composed of two or more atoms bonded or acting together.

Compound

A chemical structure containing two or more different types of atoms bonded together.

Ionic bond

A relatively weak electrostatic attraction between oppositely charged ions formed when electrons are gained or lost.

Cation

A positively charged ion formed when an atom loses one or more electrons.

Anion

A negatively charged ion formed when an atom gains one or more electrons.

Covalent bond

A very strong chemical bond formed when atoms share pairs of electrons to complete their outer shells.

Nonpolar covalent bond

A covalent bond where electrons are shared equally between atoms, resulting in a hydrophobic molecule.

Polar covalent bond

A covalent bond where electrons are shared unequally between atoms, creating partial positive and negative poles and making the molecule hydrophilic.

Hydrophobic

Describes nonpolar molecules that do not interact well with or dissolve in water.

Hydrophilic

Describes polar or charged molecules that readily interact with or dissolve in water.

Hydrogen bond

A weak electrostatic attraction between polar molecules where a hydrogen covalently bonded to N, O, or F is attracted to a partially negative region of another molecule.

Solvent

The liquid substance in a solution that dissolves another substance.

Solute

The substance in a solution that is dissolved by the solvent.

Solution

A liquid mixture formed by a solute dissolved within a solvent.

Acid

A substance that releases $\text{H}^+$ ions when placed in water, creating a higher $\text{H}^+$ concentration and a $\text{pH} < 7$.

Base

A substance that accepts or binds free $\text{H}^+$ ions in water, leading to less free $\text{H}^+$ and a $\text{pH} > 7$.

Buffer

A chemical system, usually composed of a weak acid and its corresponding weak base, that minimizes changes in $\text{pH}$.

Carbonic acid–bicarbonate buffer system

An essential physiological buffering mechanism governed by the equation $\text{H}_2\text{O} + \text{CO}_2 \leftrightarrow \text{H}_2\text{CO}_3 \leftrightarrow \text{HCO}_3^- + \text{H}^+$.