Unit 5 Atomic structure


Atom - the basic unit of all elements

Atomic number

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


Electron - the subatomic particle that moves around the nucleus

Electron diagram

Electron diagram - represents the electronic arrangement of an atom

Electronic arrangement

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

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

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

Relative atomic mass

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

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

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

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