2D (Composition of matter)

Atom

The smallest particle of matter that still has the properties of an element.

Element

A pure substance made of only one kind of atom.

Compound

A substance formed when two or more elements combine chemically in a fixed ratio.

Molecule

Two or more atoms chemically bonded together.

Atomic Nucleus

The dense center of an atom that contains protons and neutrons.

Proton

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

Neutron

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

Electron

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

Nucleus

The central part of an atom containing protons and neutrons; most of the atom’s mass is here.

Electron Cloud

The region around the nucleus where electrons are likely to be found.

Atomic Number

The number of protons in an atom

Atomic Mass

The total mass of protons and neutrons in the atom’s nucleus.

Chemical Bond

The force that holds atoms together in molecules or compounds.

Structure of Matter

The way atoms are arranged and bonded to form substances.

Physical Change

A change in the form or appearance of matter without changing its composition.

Examples of Physical Changes

Melting

Chemical Change

A change that produces a new substance with different properties.

Signs of Chemical Change

Color change

Reactant

A substance that is present before a chemical reaction takes place.

Product

A substance formed as a result of a chemical reaction.

Nuclear Change

A change in the nucleus of an atom that forms a new element.

Fusion

When two light atomic nuclei combine to form a heavier nucleus

Fission

When a heavy atomic nucleus splits into smaller nuclei

Conservation of Matter

Matter cannot be created or destroyed

Law of Conservation of Matter

During any physical or chemical change

Mixture

A physical combination of two or more substances that can be separated.

Difference Between Compound and Mixture

A compound is chemically bonded; a mixture is not.