Element
A type of pure substance. It consists of a single type of atom. It cannot be divided into smaller units.
Pure substance
Matter that contains only 1 element or compound. It has definite physical and chemical properties
Atom
The smallest component of an element having the physical and chemical properties of the element
Compound
A type of pure substance. it consists of 2 or more atoms bonded together
Mixtures
matter that has been physically combined
Atomic number
The number of positive charges or protons in the nucleus of an atom of a given element
Atomic mass
The atomic mass of a chemical element is the average mass of an atom. Atomic mass=protons+neutrons
Chemical symbol
An abbreviation or short representation of a chemical element;the symbols in the periodic table
Electron
An particle of atoms consisting of a charge of negative electricity; mass=1/1836 amu
Group
Elements forming one of the vertical columns of the periodic table.
Isotope
One of two or more atoms having the same atomic number but different mass numbers due to more or less neutrons. There are 275 isotopes of the 81 stable elements.
Mass number
The sum of the number of neutrons and protons in an atomic nucleus
Neutron
An elementary particle having no charge, Mass slightly greater than that of a proton.
Nucleus
The positively charged mass within an atom, composed of neutrons and protons, and possessing most of the mass but occupying only a small fraction of the volume of the atom
Proton
A stable, positively charged subatomic particle.
Subatomic particle
Particles that are smaller than an atom, including protons, neutrons and electrons.
Valence electrons
Electrons found on the outermost shell or orbit of an atom. These electrons are available for atomic bonding.
Atomic mass unit (AMU)
Mass of one atom of all elements