2. Sodium Chlorine

3. Sodium Chlorine PNPN PNPN Electron configuration

4. Sodium Chlorine P P Electrons Protons

5. Sodium Chlorine P P Electrons Protons Charge Electrons Protons Charge

6. Sodium Chlorine P 11 P 17 Electrons 11 Protons 11 Charge Electrons 17 Protons 17 Charge I wish my outside shell was empty I wish my outside shell was full Atom 0 0 Ion Chloride Ion 10 18 +1

7. So one sodium atom can make one chlorine atom happy So one magnesium atom can make two chlorine atoms happy Gives 2 e- Accepts 1 e-

8. Magnesium Chlorine 2+

9. Lets look at these exchanges in terms of electron configuration Sodium 1s 2, 2s 2, 2p 6, 3s 1 Chlorine 1s 2, 2s 2, 2p 6, 3s 2, 3p 5 Both atoms want full outside shells so Sodium 1s 2, 2s 2, 2p 6, 3s Chlorine 1s 2, 2s 2, 2p 6, 3s 2, 3p 1 56 0

10. So when atoms react electrons are exchanged This means the balance between an atoms protons and electrons is upset If an atom gains electrons it has more negatives than positives so overall the ion formed has is negatively charged If an atom give away electrons then it is left with more positive protons than electrons so it is left carrying a positive charge.

11. Lets look at these exchanges in terms of electron configuration Magnesium 1s 2, 2s 2, 2p 6, 3s 2 Chlorine 1s 2, 2s 2, 2p 6, 3s 2, 3p 5 Both atoms want full outside shells so Magnesium 1s 2, 2s 2, 2p 6, 3s Chlorine 1s 2, 2s 2, 2p 6, 3s 2, 3p 1 5 6 02 6 5

12. Magnesium 1s 2, 2s 2, 2p 6, 3s 2 Atom Magnesium 1s 2, 2s 2, 2p 6 ion Compare each of these Magnesium atom has 12 electrons and 12 protons Magnesium ion has 10 electrons and 12 protons Chlorine 1s 2, 2s 2, 2p 6, 3s 2, 3p 5 Atom Chlorine 1s 2, 2s 2, 2p 6, 3s 2, 3p 6 ion Chlorine atom has 17 electrons and 17 protons Chlorine ion has 18 electrons and 17 protons

13. CFU More electrons than protons means the ion has a _________ charge Atoms react because they are more stable when they have __________ outside shells When atoms have longer electron configurations than their ions the ion must be _________ charged

14. CFU Below is the electron configuration for a sodium atom ( Na) 1S 2 2S 2 2P 6 3S 1 How would the electron configuration differ for a positive Sodium ion (Na+)

15. Group 7 Group 1 reacting with Group 7 Group 1

16. Group 6 Group 1 reacting with Group 6 Group 1

17. Group 5 Group 1 reacting with Group 5 Group 1

18. Group 7 Group 2 reacting with Group 7 Group 2

19. Group 6 Group 2 reacting with Group 6 Group 2

20. Group 5 Group 2 reacting with group 5 Group 2 Group 5 Group 2

21. Group 4 Can Give four or accept four

22. How many Chlorines could an Aluminium make happy? How many Oxygens could an Aluminium make happy? How many Chlorines could a Beryllium make happy? How many Lithiums could an Oxygen help out? What is the formula of Sodium fluoride? What is the formula of magnesium fluoride? What is the formula of Aluminium fluoride? Try these questions What is the formula of Aluminium oxide?

25. Na  Na +

27. 2 Na + FeCl 2  2 NaCl + Fe

28. Before learning how to write balanced net ionic equations, we must first learn about electrolytes. Electrolytes If an aqueous solution of a compound conducts electricity, it is called an electrolyte. The ability to conduct electricity results from the dissociation of the compound into ions in solution. There are two types of electrolytes:

29. 1.Strong Electrolytes - in aqueous solution, these compounds dissociate 100% and exist as ions in solutions. They include strong acids (HCl, HBr, HI, HNO 3, H 2 SO 4 and HClO 4 ), strong bases (all the Group IA and IIA hydroxides) and all soluble salts. On the next slide is a general solubility table and in your notes is a more extensive table of common polyatomic ions

31. 1.Weak Electrolytes and/or nonelectrolytes - in aqueous solution, these compounds yield few to no ions in solution and should be represented by the molecular formula. They include: water, weak acids (any acid that isn't strong), weak bases (any base that isn't strong) and nonelectrolytes. “ Once you have learned the types of electrolytes, writing a balanced equation is best explained by example. ”

32. Example #1: Write the balanced net ionic equation for the reaction of aqueous sodium hydroxide and aqueous hydrochloric acid Step #1: Write the balanced GENERAL EQUATION - In order to write this equation, you must decide what the products are. This example problem is an acid-base reaction. The products will be a salt (NaCl) and water. After you have written the reaction, it must be balanced.

33. Step #2: Write the TOTAL IONIC EQUATION - Here, each reactant and product is studied to determine whether it dissociates in solution. If it is a strong electrolyte, it is written as ions. If it isn't a strong electrolyte it is written as a molecule. Because NaOH, HCl and NaCl are strong electrolytes they are written as ions. Water is a nonelectrolyte and should be written as a molecule.

34. Step #3: Write the NET IONIC EQUATION - Each species that does not undergo a change is called a "spectator ion". These species are removed from the equation leaving the balanced net ionic equation In this example, Na+ and Cl- are spectator ions. They do not undergo change in the reaction. Therefore, they are removed.

35. Step 1 Write a balanced net ionic equation for the reaction of solid sodium hydroxide with nitric acid. NaOH (s) + HNO 3(aq)  NaNO 3(aq) +H 2 O (l) Step 2 Full Ionic equation NaOH + H + + NO 3 -  Na + + NO 3 - + H 2 O It is important to point out that solids are not considered separate ions Step 3 Cancel out spectator ions NaOH + H +  Na + + H 2 O

36. Step 1 Write a balanced net ionic equation for the reaction of Sodium with Water. 2 Na (s) + 2H 2 O (l)  2 NaOH (aq) +H 2(g) Step 2 Full Ionic equation 2Na (s) + 2H 2 O  2Na + + 2OH - + H 2(g) It is important to point out that solids are not considered separate ions Step 3 Cancel out spectator ions 2Na (s) + 2H 2 O  2Na + + 2OH - + H 2(g)

37. We Do Step 1 Write a balanced net ionic equation for the reaction of Aqueous Silver nitrate (AgNO 3 ) with Aqueous Sodium Chloride. Step 2 Full Ionic equation Step 3 Cancel out spectator ions