Introductory Biology: Inorganic Chemistry & Properties of Water

A complete set of vocabulary flashcards reviewing essential inorganic chemistry concepts, chemical bonding, water properties, redox reactions, and pH buffers.

Element

A pure chemical substance consisting of only one type of atom.

Essential Element

An element responsible for greater than $96\%$ of the mass of living organisms, primarily carbon ($C$), hydrogen ($H$), oxygen ($O$), and nitrogen ($N$).

Trace Element

An element required by living organisms in only small amounts, such as iron, iodine, zinc, or copper.

Atom

The smallest unit of an element that retains the chemical properties of its element type.

Proton

A positively charged subatomic particle located in the atomic nucleus with an approximate mass of $1\,m_{u}$ or $1\,\text{amu}$.

Neutron

A neutral subatomic particle located in the atomic nucleus with an approximate mass of $1\,\text{amu}$.

Electron

A negatively charged subatomic particle located outside the nucleus with an approximate mass of $1/1800\,\text{amu}$.

Atomic Number

The number of protons contained within an atom, which uniquely defines the element type.

Atomic Mass

The total mass of all subatomic particles in an atom, calculated by adding the number of protons and neutrons.

Isotope

Atoms of the same element that have the same atomic number (protons) but differ in their number of neutrons and atomic mass.

Radioisotope

An unstable isotope that spontaneously decays over time into a more stable isotope.

Valence Shell

The outermost ring or shell of an atom, containing electrons that possess the highest energy level.

Valence Electrons

Electrons located in the outermost shell of an atom that determine its chemical reactivity, bonding behavior, and charge.

Covalent Bond

A strong, stable chemical bond formed when atoms share valence electrons to complete their valence shells.

Electronegativity

An atom's affinity for electrons, or its measure of ability to attract shared electrons toward its nucleus.

Nonpolar Covalent Bond

A covalent bond formed between atoms with similar electronegativities, resulting in an equal sharing of electrons.

Polar Covalent Bond

A covalent bond formed between atoms with different electronegativities, resulting in an unequal sharing of electrons and partial electrical charges.

Ion

An atom or molecule that carries a net positive or negative charge because it has gained or lost one or more electrons.

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.

Ionic Bond

A chemical bond formed by the attraction between oppositely charged cations and anions following an electron transfer.

Hydrogen Bond

A weak attraction formed when a hydrogen atom with a partial positive charge in a polar covalent bond is attracted to an atom with a partial negative charge (typically oxygen or nitrogen).

van der Waals Interactions

Weak, short-range attractions between nonpolar molecules or uncharged regions caused by temporary, random fluctuations in electron distribution.

Oxidation

A chemical reaction in which an atom, ion, or molecule loses one or more electrons and energy.

Reduction

A chemical reaction in which an atom, ion, or molecule gains one or more electrons and energy.

Cohesion

The tendency of water molecules to form hydrogen bonds with one another.

Adhesion

The tendency of water molecules to form hydrogen bonds with other substances.

Hydrophilic Substance

A water-loving substance, usually polar or ionic, that readily interacts with or dissolves in water.

Hydrophobic Substance

A water-fearing substance, usually nonpolar, that is insoluble in water and tends to cluster together in aqueous environments.

Specific Heat

The amount of heat energy required to raise the temperature of a substance; water has a high specific heat because energy is absorbed to break hydrogen bonds before molecular motion increases.

Heat of Vaporization

The amount of heat energy required to convert a liquid into a gas; water's high heat of vaporization leads to evaporative cooling.

Acid

A proton donor that dissociates in aqueous solution to yield hydrogen ions ($H^+$), resulting in a $\text{pH} < 7$.

Base

A proton acceptor that dissociates in aqueous solution to yield hydroxide ions ($OH^-$) or absorb hydrogen ions ($H^+$), resulting in a $\text{pH} > 7$.

pH

A measurement scale indicating the hydrogen ion ($H^+$) concentration of a solution in $\text{mol/L}$, where lower values indicate higher acidity.

Buffer System

A solution consisting of a weak acid and a weak base that resists drastic changes in $\text{pH}$ by accepting or donating hydrogen ions.