Mass
The sum of protons and neutrons in the nucleus of an atom.
Mass Number
The basic particle from which all elements are made; the smallest particle of an element that has the properties of that element.
Atom
An atom or group of atoms that has become electrically charged.
Ion
A one or two-letter abbreviation for an element.
Chemical Symbol
The ease and speed with which an element combines, or reacts, with other elements and compounds.
Reactivity
The average mass of all the isotopes of an element.
A tiny particle that moves around the outside of the nucleus of an atom whose weight is next to nothing compared to the weight of a proton or a neutron.
Electron
An ion that is made of more than one atom.
Polyatomic Ion
A horizontal row of elements in the periodic table.
Period
A term used to describe material that can be hammered or rolled into flat sheets.
Malleable
An atom with the same number of protons and a different number of neutrons from other atoms of the same element.
Isotope
The central core of an atom which contains protons and neutrons.
Nucleus
The attraction between bonds with opposite charges.
Ionic Bond
Elements in the same vertical column of the periodic table, also called a family.
Group
A term used to describe a material that can be pulled out into a long wire.
Ductile
The number of protons in the nucleus of an atom.
Atomic Number
A small, positively charged particle that is found in the nucleus of an atom.
Proton
A chemical bond formed when two atoms share electrons.
Covalent Bond
A substance made of two or more elements chemically combined in a specific ratio, or proportions.
Compound
The way a mineral reflects light from its surface.
Luster
An arrangement of the elements showing the repeating pattern of their properties.
Periodic Table
A small particle in the nucleus of the atom, with no electrical charge.
Neutron
A covalent bond in which electrons are shared equally.
Nonpolar Bond
The electrons that are in the highest energy level of an atom and that are involved in chemical bonding.
Valance Electron
A substance that can conduct electric current under some conditions.
Semiconductor