Chapter 3 Slides

Conservation of Mass

In chemical reactions, matter is neither created nor destroyed; total mass before equals total mass after.

Atomic Theory

The theory that all matter is composed of atoms, which are indivisible and unique to each element.

Atom

The smallest unit of an element, consisting of protons, neutrons, and electrons.

Chemical Reaction

A process that involves the rearrangement of atoms to create new substances.

Mendeleev's Periodic Table

A tabular arrangement of the chemical elements, organized by increasing atomic number and the periodicity of their properties.

Diatomic Molecule

A molecule composed of two atoms, which can be of the same or different chemical elements.

Noble Gases

Group 8A gases that are generally unreactive and do not easily form compounds.

Isotopes

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

Ion

An atom or group of atoms that has an overall charge due to the loss or gain of electrons.

Atomic Number

The number of protons in the nucleus of an atom, which determines the identity of the element.

Mass Number

The total number of protons and neutrons in an atomic nucleus.

Electron Cloud

The region surrounding the nucleus of an atom where electrons are likely to be found.

Proton

A subatomic particle found in the nucleus of an atom with a positive charge.

Neutron

A subatomic particle found in the nucleus of an atom with no charge.

Electron

A subatomic particle with a negative charge that orbits the nucleus of an atom.

Metals

Elements that are typically shiny, malleable, and conductive, located on the left side of the periodic table.

Nonmetals

Elements that are typically dull, brittle, and insulators, located on the right side of the periodic table.

Metalloids

Elements that have properties intermediate between metals and nonmetals, located between them on the periodic table.

Molecular Formula

A notation that shows the number and type of atoms in a molecule.

X-ray Crystallography

A technique used to visualize the arrangement of atoms in crystalline solids.

Subatomic Particles

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