Atoms, Ions, and Molecules

Vocabulary flashcards covering key concepts related to atomic structure, ions, and various properties of molecules.

Atomic Number

Indicates the number of protons in an atom of the element.

Atomic Mass

Combined mass of the protons and neutrons in an atom.

Matter

A substance that has mass and occupies space.

Atom

The smallest particle that exhibits the chemical properties of an element.

Element

A substance composed of only one type of atom.

Proton

A subatomic particle with a mass of 1 amu and a positive charge.

Neutron

A subatomic particle with a mass of 1 amu and no charge.

Electron

A subatomic particle with a very small mass and a negative charge.

Isotope

Atoms of the same element that have the same number of protons but differ in the number of neutrons.

Radioisotope

Chemically unstable forms of an isotope that contain excess neutrons.

Valence Shell

The outer shell of an atom that determines its chemical stability.

Ion

An atom that has gained or lost one or more electrons, resulting in an electrical charge.

Cation

A positively charged ion formed by the loss of electrons.

Anion

A negatively charged ion formed by the gain of electrons.

Covalent Bond

A bond formed between two atoms by sharing electrons.

Ionic Bond

Electrostatic attraction between a cation and an anion.

Molecular Formula

A representation of a molecule that includes the number and types of atoms.

Hydrogen Bond

A weak bond that forms between polar molecules due to an attraction between partially charged atoms.

Hydrophobic

A property of substances that do not dissolve in water.

Hydrophilic

A property of substances that readily interact with water.

pH

A measure of the relative amounts of hydrogen ions in a solution.

Buffer

A solution that minimizes changes in pH when acids or bases are added to it.

Suspension

A mixture composed of large particles that do not remain mixed unless in motion.

Colloid

A mixture composed of smaller particles that remain mixed when not in motion.

Solution

A homogeneous mixture where the dissolved substance is very small and does not scatter light.