Unit 1 Review: Atoms, Elements, and Compounds

Vocabulary-style flashcards based on the Unit 1 Review notes, covering fundamental chemistry concepts including the properties of matter, atomic structure, and chemical bonding.

Matter

Anything that has volume and mass.

Physical Change

Changes that involve changes in appearance without the formation of any new substances.

Subatomic Particles

The three types of particles in an atom: the proton, the electron, and the neutron.

Elements

Pure substances that can be divided into three categories: metals, metalloids, and non-metals.

Group (or Family)

A column of elements in the periodic table that have similar chemical properties.

Period

A horizontal row of elements in the periodic table.

Atomic Number

The number that counts the number of protons in the nucleus of an atom.

Valence Electron

An electron in the highest (outermost) occupied energy level of an atom.

Covalent Bond

A bond where a pair of electrons is shared by two atoms.

Molecule

A group of atoms joined by covalent bonds.

Exothermic Reaction

A chemical change that results in the release of heat.

Endothermic Reaction

A chemical change that results in the absorption of heat.

Kinetic Molecular Theory

A theory describing the arrangement and motion of particles in the three states of matter.

Physical Property

A characteristic of a substance that can be observed or measured, such as viscosity or state.

Ionic Compound

A type of compound that involves the attraction of oppositely charged ions.

Covalent Compound

A kind of compound that involves atoms sharing a pair of electrons.

Polyatomic Ion

A group of atoms joined by covalent bonds that carries an overall electrical charge.

Nucleus

The central part of the atom where most of the mass is located.

Electron Shells

The regions of an atom that make up most of its volume and contain electrons.

Noble Gases

The chemical family in Group 18 composed of elements that have full valence shells, making them very stable.

Alkali Metals

A family of metals located in Group 1 of the periodic table, characterized by having one valence electron.

Halogens

The chemical family in Group 17 (F, Cl, Br, I, and At) that are highly reactive non-metals.

Atomic Mass

The mass of an atom usually recorded in atomic mass units ($amu$).