1. Writing Formulas and Naming Compounds

2. SC Standards
PS-4.5
Predict the ratio by which the representative elements combine to form binary ionic compounds, and represent that ratio in a chemical formula.

3. “Perhaps one of you gentlemen would mind telling me just
what is outside the window that you find so attractive..?”
Image courtesy NearingZero.net

4. Let’s Review
Warm-up
Distinguish if the compounds on the board are ionic or covalent

5. Types of Bonds
Ionic
Covalent
Metallic
What's the Difference?

6. Binary Ionic Compounds
Binary compound – compound composed of only two elements
KCl MgCl AlCl3

7. Oxidation number – the charge on an ion
Element Charge
Oxidation number – the charge on an ion
Group 1  +1
Group 2  +2
Group 16  -2
Group 17  -1

8. Writing Chemical Formulas
In order for you to write formulas, you must know the elements charge or oxidation number +1 +2
+3 +4

9. How do we use an oxidation number?
When an element gains or loses an electron it develops a charge…
What is sodium’s oxidation number?
What is chlorine’s oxidation number?

10. How do they bond? A compound is always neutral.
The oxidation numbers always add up to zero.
In other words – the amount of positive charge must equal the amount of negative charge
Na+ + Cl NaCl

11. Transition Metals
- most transition metals can form many different ions so a roman numeral is used to show its oxidation number
copper (I)  Cu+1
copper (II)  Cu+2

12. Determining the Formula for an Ionic Compound
Write down the ions of each element
Determine the number of each of the ions it takes to make a compound with no charge
Write down the formula using subscripts to show how many of each ion it took

13. Mg+2 P-3 3(+2) + 2(-3) = 0 Mg3P2 What is the formula for the compound
that forms between
magnesium and phosphorous?
Mg+2
P-3
3(+2) + 2(-3) = 0
Mg3P2

14. You Try it!!
Write the formulas for the compounds that form between the following pairs:
Sodium and sulfur
Calcium and bromine
Iron (III) and iodine
Copper (I) and phosphorus

15. Polyatomic Ions A Group of Atoms that Function as a Single Unit in Compounds and Chemical Reactions
ammonium - NH4+1
hydroxide - OH-1
nitrate - NO3-1
carbonate - CO3-2
sulfate - SO4-2
phosphate - PO4-3

16. What is the formula for the compound between…
potassium and sulfate?
ammonium and nitride?
K+1
SO4-2
K2SO4
2(+1) + (-2) = 0
NH4+1
N-3
3(+1) + (-3) = 0
(NH4)3N

17. Name the (+) ion (always first)
Steps for Naming
1A or 2A metal or Ag, Cd, Zn, Al?
Just name it
Name the (+) ion (always first)
NH4?
Just name it
Group 3-16 metal?
Name with Roman numeral

18. Name the (-) ion
Monoatomic?
- name with -ide ending
Polyatomic?
- Just name it

19. Practice Naming Compounds…
Sodium and Sulfur Na2S
Calcium and Bromine CaBr2
Iron(III) and Iodine FeI3
Copper (I) and Phosphorus Cu3P
Sodium Sulfide
Calcium Bromide
Iron (III) Iodide
Copper (I) Phosphide

20. Covalent Bonding Electrons shared equally Electrons shared unequally
Covalent Bonds occur when electrons are being shared

21. Nonpolar Covalent Compounds
e- are shared equally
symmetrical e- density
usually identical atoms

22. Nonpolar Covalent Compounds
Examples:
The Magnificent Seven…
I2, Br2, Cl2, F2, O2, N2, H2

23. Polar Covalent Compounds
e- are shared unequally
asymmetrical e- density
results in partial charges (poles) + -

24. Polar Covalent Compounds
Examples:
H2O and HCl

25. Let’s Review
Nonpolar
Polar
Ionic
View Bonding Animations.

26. Determining Roman Numeral
Sn3(PO4)4
FeSO4 -3 ? ? -2 -3 ?
Iron (II) -3 ? -3
Tin (IV)