Element
A substance that can not be split into simpler substances by chemical means
H
Hydrogen
He
Helium
C
Carbon
N
Nitrogen
O
Oxygen
S
Sulfur
Cl
Chlorine
Na
Sodium
K
Potassium
Ca
Calcium
Mg
Magnesium
Zn
Zinc
Cu
Copper
Fe
Iron
Au
Gold
Ag
Silver
Atom
A basic part of a chemical element
Molecule
Two or more atoms chemically combined