ELEMENT
A substance that cannot be converted or broken down into simpler substances, and is the primary ingredient of matter.
ATOM
The basic unit of matter, the defining structure of an element.
PROTON
Positively charged particle in the nucleus of an atom.
ELECTRON
Negatively charged particle found in all atoms, also acts as carrier of electricity in solids.
NEUTRON
Particle with the same mass as a proton, with no electric charge. Present in the nucleus of all atoms except hydrogen.
ATOMIC NUMBER
Number of protons in the nucleus of an atom, determining an element's properties.
ATOMIC MASS
Mass of an atom, measured in atomic mass units. Value is nearly the same as the sum of protons and neutrons.
PERIOD
A row on the periodic table of elements.
FAMILY
A column in the periodic table of elements.
CONDUCTIVITY
The degree to which a material conducts electricity or heat.
LUSTRE
The way in which the surface of a mineral reflects light.
COMPOUND
Substance formed when two or more elements are chemically bonded together.
MOLECULE
Particle created when two or more elements are chemically bonded together.
PHYSICAL CHANGE
The form of matter is changed, but no chemical reaction occurs.
CHEMICAL CHANGE
A usually irreversible chemical reaction where the atoms in a substance are rearranged, creating a new substance.
