Chapter 2: The Chemical Basis of Life, I: Atoms, Molecules, and Water

These flashcards cover fundamental concepts related to the chemical basis of life, including atoms, molecules, and water.

Atom

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

Subatomic particles

Particles that make up an atom, including protons, neutrons, and electrons.

Atomic number

The number of protons in an atom, which distinguishes one element from another.

Valence electrons

Electrons in the outer shell of an atom that are available for chemical bonding.

Isotope

Forms of an element with the same number of protons but different numbers of neutrons.

Covalent bond

A chemical bond that involves the sharing of electron pairs between atoms.

Ionic bond

A chemical bond formed through the transfer of electrons between atoms, resulting in charged ions.

Hydrogen bond

A weak bond that occurs between a hydrogen atom of one polar molecule and an electronegative atom of another molecule.

Molecule

Two or more atoms bonded together.

Compound

A molecule composed of two or more different elements.

Polar covalent bond

A type of covalent bond in which electrons are shared unequally between atoms with different electronegativities.

Nonpolar covalent bond

A type of covalent bond where electrons are shared equally between atoms with similar electronegativities.

pH scale

A measurement scale used to determine the acidity or alkalinity of a solution.

Hydrophilic

Molecules or ions that readily dissolve in water.

Hydrophobic

Molecules that do not dissolve in water.

Free radical

A molecule that has an unpaired electron in its outer shell, making it highly reactive.

Chemical reaction

A process that involves the transformation of substances through the breaking and forming of bonds.

Solvent

A substance that dissolves a solute, forming a solution.

Solute

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

Concentration

The amount of solute dissolved in a unit volume of solution.

Molarity

A way to express the concentration of a solute in a solution, typically in moles per liter.

Hydrogen ion (H+)

A positively charged ion formed when an acid dissolves in water.

Hydroxide ion (OH-)

A negatively charged ion that results from the dissociation of a base in water.

Buffer

A solution that resists changes in pH upon the addition of small amounts of acid or base.

Specific heat

The amount of heat required to raise the temperature of a substance by one degree Celsius.

Heat of vaporization

The energy required to convert a liquid into a gas at its boiling point.

Heat of fusion

The amount of heat energy required to change a substance from solid to liquid.

Cohesion

The attraction between molecules of the same substance.

Adhesion

The attraction between molecules of different substances.

Octet rule

The principle that atoms tend to bond in a way that gives them eight electrons in their outermost shell.

Chemical formula

A representation of a molecule that includes the symbols for the elements and the number of atoms of each.

Electronegativity

The tendency of an atom to attract electrons in a chemical bond.

Reactants

The starting substances in a chemical reaction.

Products

The substances formed as a result of a chemical reaction.

Periodicity

The repeating pattern of chemical properties within the periodic table.