Matter. When learning nomenclature we first need to recognize the type of matter we are representing: Pure substances Mixtures Elements or Compounds Solutions or Heterogeneous eg . Au (s) eg . NaCl (s) eg . NaCl ( aq ) eg . oil + water
Elements or CompoundsSolutionsor Heterogeneous
eg. Au (s)eg. NaCl(s)eg. NaCl(aq)eg. oil + water
He (g) Na2CO3 (s) HCl(aq) rocks + sand
Use your periodic table to help to recognize and learn the names and chemical symbols of the elements.
eg. Element #27 is the metal cobalt.
Note - There are seven “diatomic” non metallic elements that are represented as follows: H2 , O2 , N2 , F2 , Cl2 , Br2 , I2
remember them by: HOFBrINCl
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*Some elements are stable and do not easily form compounds
Some metals have more than one charge and are called “multivalent”.
Metals are called cations and are POSITIVELY charged.
Non metals are called anions and are NEGATIVELY charged.
Writing Chemical Formulas
Write combining capacity (valence number) above each chemical symbol.
Criss cross the numbers and reduce subscripts to lowest terms
Eg. CO2 carbon dioxide
1=mono, 2=di, 3=tri, 4=tetra, 5=penta,
6=hexa, 7=hepta, 8=octa, 9=nona, 10=deca
Note - if the 1st nonmetal has a “1” subscript no prefix is used
Fe2+ iron (II) or ferrous (lower charge)
FeO iron (II) oxide, FeCl3 iron (III) chloride
(ferrous oxide ) (ferric chloride)
** Use this system of naming only for fyi
** note that this IONIC compound is NOT binary but TERNARY (3 or more elements) and is named differently. It contains a “polyatomic ion”.
“Revised Ternary” Compounds
Polyatomic ions can change the number of oxygens in their structure as well as the suffix
Per__ate, ____ate, ____ite, hypo___ite
(ClO4) 1- (ClO3) 1- (ClO2) 1- (ClO) 1- perchlorate chlorate chlorite hypochlorite
1 extra O normal 1 less O 2 less O
Notice the name changes but the charge remains the same.
Practice: lithium chloride tetrahydrate
prefix = hydro suffix is “ic”
Eg. H+, (ClO31- ) HClO3(aq) or “chloric acid”
Note – oxyanionprefixes are still included