Download - Unit 12 Chemical Naming and Formulas
Unit 12: Writing and Naming Chemical Formulas
Physical Science
Chemical Symbols
How to writing chemical formulas
Use the chemical symbol for each element
Usually, the element abbreviations come from the word
(He for Helium or Ti for Titanium)
Some elements have just one letter, such as H for Hydrogen or N for Nitrogen
How to writing chemical formulas
Sometimes the abbreviation does not look like the element such as:
K for PotassiumNa for SodiumPb for LeadCu for Copper Ag for SilverAu for Gold
How to writing chemical formulas
That is because their name came from Latin or other languages
K for Potassium (Kalium)Na for Sodium (Natrium)Pb for Lead (Plumbum)Cu for Copper (Cuprum)Ag for Silver (Argentum)Au for Gold (Aurum)
The 11 Odd Elements to Memorize
How to writing chemical formulas
Most elements have two letters Always capitalize the first letter and
use lower case on the second one.Example: Cobalt is Co
If you used two capitals (CO), it would be mistaken for Carbon Monoxide which has one Carbon (C) and one Oxygen (O)
Subscript Numbers
The subscript number specifies how many atoms of that element you have
N2 is a nitrogen molecule with two atoms
C2H4 has two carbons and four hydrogens.
CO2 is carbon dioxide and contains one carbon and two oxygens
If no number is listed, it means there is only one
More Examples
C2H3Cl what elements and how many of each?
More Examples
C2H3Cl what elements and how many of each?
More Examples
H2SiCl2what elements and how many of each?
More Examples
H2SiCl2what elements and how many of each?
Numbers in Front Versus Behind
What should this molecule look like?
For example CH4 =
Numbers in Front Versus Behind
What should this molecule look like? It is called Methane For example CH4 =
Numbers in Front
When there are large numbers in front, that tells you how many molecules there are.
For example 3CH4 =
Numbers in Front
When there are large numbers in front, that tells you how many molecules there are.
For example 3CH4 = 3 methane molecules
12NaOH = ?
Numbers in Front
When there are large numbers in front, that tells you how many molecules there are.
For example 3CH4 = 3 methane molecules
12NaOH = 12 different Sodium Hydroxide molecules.
Part One: Ionic Formulas
Part One: Writing Ionic Formulas
Always say the metal name first and then the non-metal with an -ide
Part One: Ionic Formulas
Part One: Writing Ionic Formulas
Example: CaCl2 would be called calcium chloride
Part One: Ionic Formulas
Part One: Writing Ionic Formulas
Example: What if you saw the name Magnesium chloride …What is the formula?
Part One: Ionic Formulas
Magnesium Chloride =
Mg+2 Cl-1
Part One: Ionic Formulas
Magnesium Chloride = MgCl2
Mg+2 Cl-1
Part One: Ionic Formulas
OK, here is one for you Magnesium Phosphate
Magnesium= Mg2+
Phosphate = PO43-
Remember, the charges have to balance
Part One: Ionic Formulas
OK, here is one for you Magnesium Phosphate
Magnesium= Mg2+
Phosphate = PO43-
Remember, the charges have to balance
2 X 3 = 6
Part One: Ionic Formulas
OK, here is one for you Magnesium Phosphate
Magnesium= Mg2+
Phosphate = PO43-
Remember, the charges have to balance
Mgx(PO4)y
+6 -6
2 X 3 = 6
Part One: Ionic Formulas
OK, here is one for you Magnesium Phosphate
Magnesium= Mg2+
Phosphate = PO43-
Remember, the charges have to balance
Mg3(PO4)2
Examples of naming for metals with multiple charges
Element Cation Name Pronounced
copper Cu+ Copper (I) copper one
Cu2+
iron Fe2+ Iron (II) iron two
Fe3+
Lead Pb2+ Lead (II) lead two
Pb4+
Tin Sn2+ Tin (II) tin two
Sn4+
Examples of naming for metals with multiple charges
Element Cation Name Pronounced
copper Cu+ Copper (I) copper one
Cu2+ Copper (II) copper two
iron Fe2+ Iron (II) iron two
Fe3+ Iron (III) iron three
Lead Pb2+ Lead (II) lead two
Pb4+ Lead (IV) lead four
Tin Sn2+ Tin (II) tin two
Sn4+ Tin (IV) tin four
Part One: Ionic Formulas
What about Iron (II) Oxide
Step One: Determine the charges Iron (II) = Fe2+ and Oxide = O2-
Part One: Ionic Formulas
What about Iron (II) Oxide
Step One: Determine the charges Iron (II) = Fe2+ and Oxide = O2-
Step Two: See how to balance the charges
Step Three: Find the combination that balances
Part One: Ionic Formulas
What about Iron (II) Oxide
Step One: Determine the charges Iron (II) = Fe2+ and Oxide = O2-
Step Two: See how to balance the charges
Step Three: Find the combination that balances
Iron (II) Oxide = FeO
How do you know if you use Roman numerals? Do not use Roman Numerals for groups 1 or 2 as
they are always (+1) and (+2) accordingly.
K = +1 and Ca = +2+1
+2
How do you know if you use Roman numerals? Do not use Roman numerals for anything in the
P-block since they tend to form covalent bonds.
The exceptions are Tin (Sb) and Lead (Pb)
How do you know if you use Roman numerals? Do not use Roman numerals for Zn or Ag
because they have dominant oxidation states that rarely change:
Ag = +1 and Zn = +2.
Prefixes for Covalent Bonds
1 = Mono Carbon Monoxide (CO)Example
Prefixes for Covalent Bonds
1 = Mono Carbon Monoxide (CO)
2 = Di Carbon Dioxide (CO2)
Example
Prefixes for Covalent Bonds
1 = Mono Carbon Monoxide (CO)
2 = Di Carbon Dioxide (CO2)
3 = Tri Nitrogen Triiodide (NI3)
Example
As you can see, you don’t label the first with a prefix unless it is more than one
Prefixes for Covalent Bonds
1 = Mono Carbon Monoxide (CO)
2 = Di Carbon Dioxide (CO2)
3 = Tri Nitrogen Triiodide (NI3)
4 =Tetra Dinitrogen Tetroxide (N2O4)
Example
As you can see, you don’t label the first with a prefix unless it is more than one
Prefixes for Covalent Bonds
1 = Mono Carbon Monoxide (CO)
2 = Di Carbon Dioxide (CO2)
3 = Tri Nitrogen Triiodide (NI3)
4 =Tetra Dinitrogen Tetroxide (N2O4)
5 = Penta Phosphorus Pentachloride (PCl5)
Example
As you can see, you don’t label the first with a prefix unless it is more than one
Prefixes for Covalent Bonds
1 = Mono Carbon Monoxide (CO)
2 = Di Carbon Dioxide (CO2)
3 = Tri Nitrogen Triiodide (NI3)
4 =Tetra Dinitrogen Tetroxide (N2O4)
5 = Penta Phosphorus Pentachloride (PCl5)
6 = Hexa Sulfur Hexaflouride (SF6)
Example
As you can see, you don’t label the first with a prefix unless it is more than one
Drawing Covalent Compounds
In general, the first named compound is the central compound.
Sulfur dioxide
Nitrogen Triiodide
Carbon Tetrachloride