Table of Contents
1.Naming Ionic Compounds Type I
2.Naming Ionic Compounds Type II
3.Naming Covalent Compounds
4.Naming Polyatomic Compounds
Welcome to your
“NEW”
Periodic Table• This periodic table identifies
several aspects of the
elements we already know.
• This IS a reference tool.
• This IS NOT a cheat sheet.
• You will only ever be
allowed to use ONE of your
periodic tables at a time.
Ionic Compounds Without Transition
MetalsIonic compounds are formed when a metal gives up its electrons to a non-metal. Basically if the
compound contains a metal, it is ionic. But there are different sets of rules for transition
metals. A transition metal is an element with an atomic number of 21 to 30, 39 to 48 or 57 to
80.
So for a compound with any other metal, apply these rules:
1. The metal ion's name does not change regardless of charge.
2. The non-metal's name ends in the suffix “-ide”.
For example: AlCl3 = aluminum chloride
Na2S = sodium sulfide
K2O = potassium oxide
MgH2 = magnesium hydride
Notice how the little numbers (subscripts) do not affect the way we name them. In going
backwards (from name to formula), we will have more fun. In such a case the total charge of
the (+) and (-) ions in the compound has to be ZERO.
Example: What is the correct chemical
formula for Calcium Phosphide?
Here, we have to consider the common charges for calcium and phosphorus,
which are +2 and -3, respectively. Calcium, if you recall, typically loses two
electrons to get a noble gas electron arrangement, and phosphorus needs three
more electrons.
Ca+2 and P-3
One of each would create a sum of 2 + (-3) = -1. To get a sum of zero, we need
three Ca+2 ions and two P-3 for a total of 3(2)+ 2(-3) = 0.
So the answer is Ca3P2.
Other examples: potassium oxide : K+1 and O-2 yields K2O
aluminum bromide: Al+3 and Br-1 yields AlBr3.
Kriss-Kross Method for determining
Chemical Formulas
P32
Ca
P3 2
Ca
• Using the Kriss-Kross Method helps us to determine the chemical formula for a
chemical compound when given a written equation.
• For example you have been given the compound Calcium Phosphide. Below you
will see an example of how to use this method to determine its formula.
P3-2+
CaStep 1: Write out the ion
forms of both elements.
Step 2: Take the
absolute value of the
charge and Kriss-Kross
their positions to the
opposite element.
Step 3: Write the
chemical equation in its
reduced form.
Ionic Compounds with Transition Metals
The only difference here is that we have to specify
the charge of the transition metal ion by using a
Roman numeral, and keep in mind that a transition
metal is an element with an atomic number of 21 to
30, 39 to 48 or 57 to 80.
The reason we do this is not for the sake of
nostalgia for bygone Roman numerals nor to imitate
movie credits. Because transition metals can assume
more than one charge, we have to specify which one
is involved
Example: manganese(II) oxide contains Mn+2 and O-2.
So we just need one of each and the formula
becomes MnO.
Copper(I) oxide is Cu2O.
To go backwards, we need to figure out the charge
of the transition metal.
Roman
NumeralNumber
I 1
II 2
III 3
IV 4
V 5
VI 6
VII 7
Naming Rules and Prefixes
Step 1: Name the 1st element with its name
Step 2: Name the 2nd element with the suffix “-ide”
Step 3: Use the prefixes to denote the number of atoms of each element.
Step 4: Do NOT use the “mono” prefix on the 1st element.
The only time we drop a prefix is if the mono is to appear at the
beginning of the name.
1 - mono
2 - di
3 - tri
4 - tetra
5 - penta
6 - hexa
7 - hepta
8 - octa
9 - nona
10 - deca
Naming Examples
Compound Formula: OCl2First Element: Oxygen
Second Element: dichloride
Compound Name: Oxygen
Dichloride
Compound Formula: PCl51st Element: Phophorus
2nd Element: pentachloride
Compound Name: Phosphorus
pentachloride
Check for Understanding
Name Compound FormulaUse the Nomenclature rules to determine the correct
names of the following compounds.
CO
CO2
CH4
Compound Formula NameUse the Nomenclature rules to determine the correct
compound formulas of the following compounds.
dinitrogen pentoxide
phosphorus trichloride
Dihydrogen monoxide
Naming Polyatomic Compounds
When metals are bonded to polyatomic ions, which consist of two or more
atoms with one overall charge, the same rules apply, but you have to learn
the names and charges of common polyatomic ions.
Na2CO3 = sodium carbonate. ( This is a useful chemical in purifying others; it is
sometimes called washing soda)
KNO3 = potassium nitrate ( This is an ingredient of gunpowder and it is also found
in fertilizer.)
To go backwards: Aluminum sulfate
This has Al+3 and SO4-2. To get a sum charge of ZERO, we need two aluminum
ions and three sulfates, so the formula becomes Al2(SO4)3. Notice that when
there is more than one polyatomic group, we make use of brackets.
List of Polyatomic IonsWhile memorization of these are not required it would be a
good idea to know the ones with a star next to them.
Nomenclature Summary
Use this chart to help determine the names of
chemical compounds
Does the compound contain a metal?
Is the metal a TRANSITION METAL?
Use I, II, III, IV, V to indicate the charge
of the metal
Don’t use roman numerals; Don’t use
prefixesCompound is COVALENT; Mono=1,
Di=2, Tri=3, Tetra=4, Penta=5
YES
YES
NO
NO