1. What’s in a name?

2. LOL ASAP FYI BRB
Chemical formulas are shorthand method.

3. What are chemical formulas? What can a chemical formula tell us?
Number of atoms of a particular element present in a chemical compound
Ex. CO2, NO2
For ionic compounds, the ratio between the positive and negative ions within the chemical compound
Ex. NaCl, MgCl2
Monoatomic ions—
Ions originating from ONE atom
Cation—named by element
Anion—named by element, drop ending and add –ide ending
Ex. O-2, N-3, Mg+2

4. C6H12O6

5. Binary Compounds—Writing Chemical formulas
1) Cation, Anion. (write element symbols)
2) Write oxidation number/charge on each element.
3) Balance charges by the smallest common multiplier between the two elements. Charges must add to 0 for a neutral compound.
4) Add the subscripts for each element in the chemical compound.
Dealing with two elements “bi” –metal/nonmetal

6. Example 1: Sodium chloride “salt”
NaCl

7. Example 2: Aluminum oxide
Al2O3

8. You try…..
Magnesium bromide
Lithium chloride
MgBr2
LiCl

9. 5) If the first element is a transition element, the oxidation number or charge of the element is given by a Roman numeral (I, II, III, IV, etc.) following the element name. Exceptions: Ag+1 and Zn+2—they will always have these charges.

10. Example 3: Tin (IV) sulfide
SnS2

11. Example 4: Iron (III) oxide
Fe2O3

12. You Try….. 1) Zinc oxide 2) Mercury (II) fluoride
1) ZnO
2) HgF2

13. Try….. Calcium chloride Copper (I) oxide Sodium bromide
Potassium sulfide
Calcium oxide
CaCl2
Cu2O
NaBr
KS2
CaO

14. Binary Compounds—Writing Chemical formulas (Cont.)
6) If a binary compound has a prefix or prefixes in front of an element name, these prefixes are the subscripts for that element in the chemical formula. Prefixes represent the number of element atoms present in a molecule of the chemical compound.

15. Prefixes 1 mono 6 hexa 2 di 7 hepta 3 tri 8 octa 4 tetra 9 nona
5 penta deca

16. Example 1: Carbon monoxideCO

17. Example 2: Carbon dioxide
CO2

18. You Try….. Diphosphorus trioxide Iodine heptafluoride
Carbon tetrachloride

19. Polyatomic Chemical Compounds—Writing Chemical Formulas.
1) Cation, Anion—reference table, Element Symbols 2) Immediately put ( ) around polyatomic ion 3) Write the oxidation number/charge on each element and polyatomic ion. 4) Balance charges by the smallest common multiplier. Charges must add to 0 for a neutral compound. 5) Add the subscripts for each element/polyatomic ion and drop the ( ) around polyatomic if you can. *Polyatomic ions: place polyatomic ions in parentheses when adding subscript (ex. (NO3)2)
**1st step—write the element symbol or polyatomic ion symbol for each.
IMMEDIATELY enclose polyatomic ions in ()

20. Example 1: Silver nitrate
AgNO3

21. Example 2: Magnesium acetate
Mg (CH3CO2)2

22. You try….. 2) Calcium carbonate 3) Magnesium Phosphate
1) Ammonium chloride
2) Calcium carbonate
3) Magnesium Phosphate
4) Ammonium sulfate
NH4Cl
CaCO3

23. Classwork: 1) Potassium sulfate 12. Sodium phosphate
2) nitrogen dioxide Dinitrogen pentaoxide
3) sulfur tetrabromide Carbon tetrahydride
4) magnesium phosphate Calcium nitrate
5) sodium sulfate
6) phosphorus pentachloride
7) selenium trichloride
8) chromium (III) nitrite
9) iodine dioxide
10) magnesium hydroxide
11) Mercury (II) hydroxide