2. Chemical Formulas and Chemical Compounds Heart cell rhythm depends on the opening and closing of a complex series of valves on the cell membrane, called ion channels. Some valves let certain ions like potassium (K+) flow out, others let different ions like sodium (Na+) flow in. There are also pumps that actively move ions one direction or another.

3. Ions Cation: A positive ion Mg 2+, NH 4 + Anion: A negative ion Cl , SO 4 2  Ionic Bonding: Force of attraction between oppositely charged ions.

4. Predicting Ionic Charges Group 1: Lose 1 electron to form 1+ ions H+H+H+H+ Li + Na + K+K+K+K+

5. Predicting Ionic Charges Group 2: Loses 2 electrons to form 2+ ions Be 2+ Mg 2+ Ca 2+ Sr 2+ Ba 2+

6. Predicting Ionic Charges Group 13: Loses 3 Loses 3 electrons to form 3+ ions B 3+ Al 3+ Ga 3+

7. Predicting Ionic Charges Group 14: Lose 4 Lose 4 electrons or gain 4 electrons? Neither! Group 14 elements rarely form ions.

8. Predicting Ionic Charges Group 15: Gains 3 Gains 3 electrons to form 3- ions N 3- P 3- As 3- Nitride Phosphide Arsenide

9. Predicting Ionic Charges Group 16: Gains 2 Gains 2 electrons to form 2- ions O 2- S 2- Se 2- Oxide Sulfide Selenide

10. Predicting Ionic Charges Group 17: Gains 1 Gains 1 electron to form 1- ions F 1- Cl 1- Br 1- Fluoride Chloride Bromide I 1- Iodide

11. Predicting Ionic Charges Group 18: Stable Noble gases do not form ions! Stable Noble gases do not form ions!

12. Predicting Ionic Charges Groups 3 - 12: Many transition elements Many transition elements have more than one possible oxidation state. have more than one possible oxidation state. Iron(II) = Fe 2+ Iron(III) = Fe 3+

13. Predicting Ionic Charges Groups 3 - 12: Some transition elements Some transition elements have only one possible oxidation state. have only one possible oxidation state. Zinc = Zn 2+ Silver = Ag +

14. Binary Ionic Compounds Binary ionic compounds means two ions, one that is positive in charge (cation) one that is negative in charge (anion) that react to form a compound.

15. Naming Ionic Binary Compounds 1.The ion with the positive charge (cation) is always written before the ion with the negative charge (anion) 2.The first word is the name of the element of which the cation originally came. (Example: Na + would be called Sodium) 3.The last word is the name of the element of which the anion originally came. (Example: Cl - would become chlorine, but the first part of the word is used and -ide is added to the end, so the last word would be Chloride.) 4.Put the two words together and that is the name of the compound. (Example: Na + and Cl - would become Sodium Chloride.)

16. Naming Ionic Compounds 1. Cation first, then anion 2. Monatomic cation = name of the element Ca 2+ = calcium ion 3. Monatomic anion = root + -ide Cl  = chloride CaCl 2 = calcium chloride

17. Naming Ionic Compounds (continued) -some metal forms more than one cation -use Roman numeral in name PbCl 2 Pb 2+ is cation PbCl 2 = lead(II) chloride Metals with multiple oxidation states

18. Polyatomic Ions Polyatomic Ions are ions that contain a number of ions. There is no way to learn how to write their names, except to commit them to memory

19. Common Polyatomic Ions (VIP) IonNameIonName NH 4 + AmmoniumO 2 -2 Peroxide NO 2 - NitriteCrO 4 -2 Chromate NO 3 - NitrateCr 2 O 7 -2 Dichromate SO 3 -2 SulfiteMnO 4 - Permanganate SO 4 -2 SulfateC2H3O2-C2H3O2- Acetate HSO 4 - Hydrogen SulfateClO 4 - Perchlorate OH - HydroxideClO 3 - Chlorate CN - CyanideClO 2 - Chlorite PO 4 -3 PhosphateClO - Hypochlorite HPO 4 - Hydrogen PhosphateHCO 3 - Hydrogen Carbonate H 2 PO 4 - Dihydrogen PhosphateCO 3 -2 Carbonate

20. Writing Ionic Compound Formulas Example: Ammonium sulfate 1. Write the formulas for the cation and anion, including CHARGES! NH 4 + SO 4 2- 2. Check to see if charges are balanced. 3. Balance charges, if necessary, using subscripts. Use parentheses if you need more than one of a polyatomic ion. Not balanced! ( ) 2

21. Writing Ionic Compound Formulas Example: Iron(III) chloride 1. Write the formulas for the cation and anion, including CHARGES! Fe 3+ Cl - 2. Check to see if charges are balanced. 3. Balance charges, if necessary, using subscripts. Use parentheses if you need more than one of a polyatomic ion. Not balanced! 3

22. Writing Ionic Compound Formulas Example: Aluminum sulfide 1. Write the formulas for the cation and anion, including CHARGES! Al 3+ S 2- 2. Check to see if charges are balanced. 3. Balance charges, if necessary, using subscripts. Use parentheses if you need more than one of a polyatomic ion. Not balanced! 23

23. Writing Ionic Compound Formulas Example: Magnesium carbonate 1. Write the formulas for the cation and anion, including CHARGES! Mg 2+ CO 3 2- 2. Check to see if charges are balanced. They are balanced!

24. Writing Ionic Compound Formulas Example: Zinc hydroxide 1. Write the formulas for the cation and anion, including CHARGES! Zn 2+ OH - 2. Check to see if charges are balanced. 3. Balance charges, if necessary, using subscripts. Use parentheses if you need more than one of a polyatomic ion. Not balanced! ( ) 2

25. Writing Ionic Compound Formulas Example: Barium nitrate 1. Write the formulas for the cation and anion, including CHARGES! Ba 2+ NO 3 - 2. Check to see if charges are balanced. 3. Balance charges, if necessary, using subscripts. Use parentheses if you need more than one of a polyatomic ion. Not balanced! ( ) 2

26. Writing Ionic Compound Formulas Example: Aluminum phosphate 1. Write the formulas for the cation and anion, including CHARGES! Al 3+ PO 4 3- 2. Check to see if charges are balanced. They ARE balanced!