Chemistry Review: Structure of Water and Chemical Bonds

Vocabulary flashcards covering key chemical concepts, bonding types, periodic table structure, and the unique properties of water.

Matter

Anything that takes up space and has mass.

Element

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

Compound

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

Essential elements

Elements of the 92 naturally occurring elements that are required by an organism to survive and reproduce (20-25%).

Trace elements

Elements of the 92 naturally occurring elements that are required by an organism in very small quantities.

Atomic number

The number of protons in an atom.

Atomic mass

The number of protons plus neutrons averaged over all isotopes.

Valence shell

The outermost layer of electrons in an atom.

Octet rule

The principle stating that elements will gain, lose, or share electrons to complete their valence shell and become stable.

Chemical Bonds

An attraction between two atoms, resulting from the sharing or transferring of valence electrons.

Electronegativity

The measure of an atom's ability to attract electrons to itself.

Covalent bonds

Bonds formed when two or more atoms share electrons, usually between two nonmetals.

Nonpolar covalent bond

A covalent bond in which electrons are shared equally between two atoms.

Polar covalent bond

A covalent bond created by unequal sharing of electrons between atoms, resulting in partial charges.

Ionic bonds

The attraction between oppositely charged atoms (ions), formed when there is a transfer of electrons.

Cation

A positively charged ion.

Anion

A negatively charged ion.

Hydrogen bonds

A bond formed when the partially positive hydrogen atom in one polar covalent molecule is attracted to an electronegative atom in another polar covalent molecule.

Intermolecular bond

A bond that forms between molecules.

Cohesion

The attraction of molecules for other molecules of the same kind ($\text{H}_2\text{O}$ to $\text{H}_2\text{O}$).

Adhesion

The attraction of water molecules to other molecules that are polar or have a charge.

Capillary Action

The upward movement of water due to the combined forces of cohesion, adhesion, and surface tension.

High Specific Heat

The property of water to resist changes in temperature because heat must be absorbed to break hydrogen bonds and released when hydrogen bonds form.

Evaporative cooling

The process in which the surface water evaporates from becomes cooler.

Solution

A homogeneous mixture of two or more substances.

Solvent

The dissolving agent in a solution.

Solute

The substance that is dissolved in a solution.

pH

A measure of how acidic or basic (alkaline) a solution is.

Acid

A substance that releases hydrogen ions ($\text{H}^+$) when dissolved in water.

Base

A substance that accepts $\text{H}^+$ or releases hydroxide ions ($\text{OH}^-$) when dissolved in water.

Buffer

A solution that resists changes in pH when an acid or base is added.