1. ELEMENT RIDDLES Cobalt
1. What you call a cruel and annoying brother _________ 
Bromine
2. Middle aged men sometimes
________
Cobalt

2. Ionic Compounds:
Names and Formulas

3. Writing Chemical Formulas
Compounds are pure substances made of more than one kind of atom joined together.
The atoms are held together with chemical bonds.
Compounds come in two basic types: covalent and ionic.

4. Writing Chemical Formulas
Covalent compounds share electrons to form molecules.
Example: water

5. Ionic Compounds
Ionic solids exist as a solid in the form of an ionic lattice.
The positive ions attract all of the negative ions, and vice versa.

6. Ionic Compounds
In ionic compounds, atoms gain or lose electrons to form ions.
Example: NaCl

7. Polyatomic Ions Covalent and ionic bonds can occur together
A molecule can gain or lose electrons to become charged, forming a polyatomic ion.
Polyatomic ions form compounds like other ions.
Example: Ammonium ion (NH4+)
There are many types of polyatomic ions, but they occur in a few basic shapes.

8. Ion Charge

9. ELEMENT RIDDLES Seaborgium
1. If you throw a heavy rock into a pond, it will _________ 
Zinc
2. What caused the “Titanium” (Titanic) to sink was a giant
________
Seaborgium

10. Naming Monovalent Compounds
Each different compound has its own name which tells what elements are in the compound
Monovalent elements have only one ion charge
e.g. lithium (1+), calcium (2+), aluminum (3+)
When naming, there are 2 steps to follow:
Write the name of the metallic element first
Write the name of the non-metallic element second and change its ending to “-ide”

11. Some tricky endings:
hydrogen – hydride oxygen – oxide
phosphorus – phosphide nitrogen – nitride
fluorine - fluoride
chlorine- chloride
bromine- bromide
iodine- iodide

12. Examples:
Magnesium + oxygen  magnesium oxide
Chlorine + calcium  calcium chloride
ZnO  ___zinc oxide
Al2S3  ___aluminum sulphide

13. Writing Monovalent Formulas
To write the chemical formula of a compound, do the following:
Write the metal and non-metal elements in their ion form (metal always goes first)
Rewrite the elements without ion charges, and then crisscross the numbers (omit + and - signs)
the numbers are written as subscripts
If there is a common factor, reduce the subscripts
the number 1 is never written

14. Examples

15. Naming Multivalent Compounds
Also referred to as transition metals, these only occur after atomic number 20 and have more than one ion charge
e.g. lead (2+, 4+), iron (3+, 2+), gold (3+, 1+)
When naming these compounds, you must use Roman Numerals to indicate which ion charge has been used
I = 1
II = 2
III = 3
IV = 4
V = 5
VI = 6

16. Naming Multivalent Compounds
There are 2 steps to follow:
Write the name of the metallic element first, the non-metallic element second and change its ending to “-ide”
Work backward from the non-metal ion charge to determine the metal ion charge and write the roman numeral in brackets after the metal

17. Naming Multivalent Compounds
 Examples
AuCl  Gold (I) Chloride
Fe2O3  iron (III) oxide
MnS2  manganese (IV) sulphide

18. ELEMENT RIDDLES Tungsten Antimony 1. To dislike riches _______
2. If you eat lots of blueberries, you might end up with a
________
Tungsten

19. Writing Multivalent Formulas
To write the chemical formula, do the following:
Write the metal and non-metal elements in their ion form
the Roman numeral tells you which ion charge to use for the metal
Rewrite the elements without ion charges, and then crisscross the numbers
If there is a common factor, reduce the subscripts

20. Examples

21. Naming Polyatomic Compounds
Group of atoms with a common name and ion charge.
e.g. hydroxide :OH-, sulphate: SO42-
It is simple to identify compounds containing polyatomic ions because the formula has 3 or more different elements
There are 2 steps to follow:
Positive polyatomic ions are written first, like metals
Negative polyatomic ions are written second and the name of the ion is not changed

22. Naming Polyatomic Compounds
Examples
Calcium + nitrate  calcium nitrate
Hydrogen + dichromate  hydrogen dichromate
K2SO4  potassium sulphate
KMnO4  potassium permanganate

23. Writing Polyatomic Formulas
To write the chemical formula, do the following:
Write the metal and non-metal elements in their ion form (polyatomic is always written in brackets)
Rewrite the elements without ion charges, and then crisscross the numbers (keep the brackets)
If there is a common factor, reduce the subscripts
if you have only one of a polyatomic group, omit the brackets

24. Examples