Element
A substance made of one type of atom only
Atom
The smallest particle of an element that can exist
Ion
An atom that has gained or lost electron/s will have a net charge
Molecule
2 or more atoms chemically bonded together
Compound
2 or more ions chemically bonded together
Electron
A negative charged sub-atomic particle
Neutron
A neutral sub-atomic particle
Proton
A positively charged sub-atomic particle
Nucleus
The middle of an atom (or ion)
Energy level
Areas around a nucleus where electrons are found
Atomic number
The number of protons in the nucleus of an atom
Mass number
The number of Protons + Neutrons in the nucleus of an atom
Group
The column (groups go to the ground) on a periodic table, all atoms in the same group will have the same number of valence electrons.
Period
A row on the periodic table, all atoms in the same period will have valence electrons in the same energy level.
Electron configuration
A simplification of where the electrons are found eg 2,8,8,18
Valence level
The outermost occupied energy level
Valence electrons
Electrons found in the valence level
Cation
a positively charged ion (same number of protons as atom but fewer electrons).
Anion
a negatively charged ion (same number of protons as atom but more electrons).
Reactant
Substances on the left hand side of the arrow, they are used up in a reaction.
Product
Substances on the right hand side of the arrow, they are formed in a reaction.
Chemical equation (word)
Reactants and products written as an equation in words eg Hydrogen + oxygen → Water
Electrically neutral
When charged particles are equal and opposite (ie electrons and protons / Cations and anions) so the charges cancel out and there is no overall charge
Mixture
A combination of two or more substances in any proportion
