Atom - the basic unit of all elements

Atomic number - the number of protons in an atom of that element

Electron - the subatomic particle that moves around the nucleus

Electron diagram - represents the electronic arrangement of an atom

Electronic arrangement - the way in which electrons are arranged in an atom

Element - a pure chemical substance consisting of a single type of atom which divided into metals, metalloids, and non-metals

Isotope - different atoms of an element which have the same number of protons but a different number of neutrons

Mass number - the sum of the numbers of protons and neutrons in an atom

Metal - a class of chemical elements which usually are shiny, have high melting and boiling points, are good conductors of heat and electricity and can be bent or hammered into shape

Metalloid - are elements that have some properties of both metals and non-metals

Neutron - the subatomic particle that bears no electrical charge but a mass similar to a proton

Non-metal - a class of chemical elements which usually are dull in appearance if they are solids, have low melting and boiling points and are non-conductors of electricity, poor conductors of heat and brittle

Nucleus - the central part of an atom and contains protons and neutrons with electrons moving around it

Orbit - the circular paths in which electrons move around the nucleus in the Bohr's model

Orbital - the region in which there is a high probability of finding the electron(s) of an atom

Proton - the subatomic particle that bears a small positive electrical charge and a mass similar to a neutron

Relative abundance - the proportion of each isotope in a naturally occurring sample of the element

Relative atomic mass - the weighted average relative isotopic mass of all the naturally occurring isotopes of that element on the ¹²C = 12.00 scale

Relative isotopic mass - the relative mass of one atom of that isotope on the ¹²C =12.00 scale

Shell - electrons move around the nucleus in circular orbits called shells

Subatomic particle - An atom consists of three types of subatomic particles: protons, neutrons and electrons