Study Guide: Chapter 2 - The Nature of Molecules and the Properties of Water

Flashcards covering key vocabulary and concepts related to Chapter 2 of Chemistry and the Properties of Water.

Matter

Anything that has mass and occupies space.

Atom

The smallest unit of matter, consisting of protons, neutrons, and electrons.

Proton

A positively charged particle found in the nucleus of an atom.

Neutron

A neutral particle found in the nucleus of an atom.

Electron

A negatively charged particle that orbits the nucleus of an atom.

Atomic number

The number of protons in the nucleus of an atom.

Atomic mass

The total number of protons and neutrons in the nucleus of an atom.

Ion

A charged atom, which can be a cation (positive) or an anion (negative).

Isotope

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

Half-life

The time taken for half of the radioactive isotopes in a sample to decay.

Valence electrons

Outermost electrons that determine an atom's chemical properties.

Octet Rule

States that atoms tend to gain, lose, or share electrons to achieve a full outer shell of 8 electrons.

Oxidation

The loss of electrons by an atom or molecule.

Reduction

The gain of electrons by an atom or molecule.

Ionic bond

A chemical bond formed between oppositely charged ions.

Covalent bond

A bond formed when atoms share electrons.

Polar covalent bond

A type of covalent bond with unequal sharing of electrons.

Nonpolar covalent bond

A type of covalent bond with equal sharing of electrons.

Hydrogen bond

Weak attractions between polar molecules.

van der Waals forces

Weak, non-directional forces between close atoms.

Reactants

Substances that undergo a chemical change in a reaction.

Products

Substances formed as a result of a chemical reaction.

Cohesion

The tendency of water to stick to itself, creating surface tension.

Adhesion

The tendency of water to stick to other polar substances.

Specific heat

The amount of heat needed to raise the temperature of a substance.

Heat of vaporization

The amount of energy required to convert water from liquid to gas.

Hydrophilic

Substances that can dissolve in water.

Hydrophobic

Substances that do not dissolve in water.

pH

A measure of hydrogen ion concentration; low pH indicates acidity, high pH indicates basicity.

Acid

A substance that donates hydrogen ions (H+) in solution.

Base

A substance that accepts hydrogen ions (H+) in solution.

Buffer

A solution that stabilizes pH by donating or absorbing hydrogen ions.