Reminder

1. Reminder • When the timer reaches 0: • You must have your notebook out and open, • Have a pen or pencil ready • And, if there was homework, have it out on your desk. • Then, copy the objective and ANSWER the Do Now questions.

2. 4 January 2010 • Objective: SWBAT differentiate between ionic and covalent bonding. • Do Now: • Write the name for Pb(NO3)2 • Is Pb(NO3)2 ionic or covalent? • Name one PROPERTY of ionic compounds.

3. Announcements • Four days this week – Covalent compounds – properties, names, drawing diagrams. • Two days next week – shapes of covalent molecules. • Then, midterm review (4 days)!! • Midterms are the (short) week of January 18.

4. Announcements • I will post missing assignments for quarter 2 tomorrow in room 104. • If you haven’t taken the Ions and Ionic Compounds test, you must do so by Friday!!! • Seating survey tomorrow; new seats later this week.

5. What do you remember about ionic bonding and ionic compounds? • Which elements? Electronegativity? • How does it work? • Properties of ionic compounds?

6. Ionic or Covalent? • NaCl • NO2 • N2Br • NaI • CaS

7. Ionic or Covalent? • KNO3 • Fe(CrO4)2 • Cu(OH)2 • BaI • F2

8. Ionic or Covalent? • O2 • AgCl • AgNO3

9. Covalent Bonding

10. Covalent Bonding • two or more non-metals • all with high electronegativity • ions are NOT formed!! • atoms share some valence electrons(not transfer) to make a full octet of 8

11. F • usually each atom donates (shares) one of each pair of electrons Electron Pair Shared by both atoms One e- shared by each atom F

12. number of bonds formed depends on the number of e- required to fill the valence shell • noble gases = full valence, rarely form compounds • octet rule: usually, atoms want 8 valence e- (H, He need 2)

13. Ex: C has 4 valence e- • needs 4 more to form a full octet • C forms 4 bonds • Ex: F has 7 valence e- • needs 1 more to form a full octet • F makes one bond • Nitrogen? Oxygen?

14. Demonstration! • (the return of the little white balls)

15. Properties of Covalent Compounds • covalent bonds = strong • forces between molecules = weaker • covalent molecules are easily separated from one another • soft solids (l or g at room temp) • do not conduct electricity • not very soluble in water • low melting/boiling points (liquid or gas at room temperature)

16. Examples of Covalent Compounds

17. Videos! • http://www.youtube.com/watch?v=QqjcCvzWwww • http://www.youtube.com/watch?v=yjge1WdCFPs&feature=PlayList&p=8D43FC9FA07913EF&playnext=1&playnext_from=PL&index=23 • http://www.youtube.com/watch?v=F54rqDh2mWA

18. 6 January 2010 • Objective: SWBAT name and write formulae for covalent compounds. • Do Now: • What is the difference between ionic and covalent compounds? (Write at least two complete sentences.)

19. Agenda • Seating/success survey • Naming covalent compounds • Writing formulae for covalent compounds

20. Announcements • Missing work is on bulletin board in 104. • Did you take the Ions and Ionic Compounds test? • Last day to hand in missing work: • Tues. Jan. 12 • Midterm: Wed. Jan. 20 • 10:20 am-12:10 pm

21. How did we name ionic compounds?

22. Naming Covalent Compounds • P2O5 • What do the little numbers (subscripts) mean?! • Subscripts = The number of atoms of each element!! • Use prefixes to communicate how many atoms of each element.

23. Prefix System • 1 – mono* • 2 – di • 3 – tri • 4 – tetra • 5 – penta • *never use mono if the FIRST element listed in a compound has one atom. • The SECOND element gets an “-ide” ending

24. Write names or formulae • NO2 • CO2 • PCl5 • P2S4 • Nitrogen trioxide • Carbon monoxide • Dinitrogentetrahydride

25. Name these covalent compounds • NH3 • CH4 • CF4 • H2O • P3O5 • SBr2 • P2O3 • What is the ratio of nitrogen atoms to hydrogen atoms in NH3?

26. Write formulae • Dinitrogen monoxide • Carbon tetrachloride • Oxygen difluoride • Sulfur trioxide • Dichlorineoctoxide • Sulfur dibromide • Dioxide difluoride • Xenon tetrafluoride

27. Homework • Week 18 Homework #6-7

28. 7 January 2010 • Objective: SWBAT draw Lewis dot structures for covalent compounds. • Do Now: • P2O5 • a) Ionic or covalent? Name it. • b) What is the ratio of phosphorus to oxygen? • c) Name one property you would expect this compound to have.

29. Agenda • Go over homework (correct it!) • How to draw Lewis dot structures • Lots of practice on whiteboards! Homework: Finish Week 18 Homework – due tomorrow

30. Announcements • Missing work is on bulletin board in 104. • Did you take the Ions and Ionic Compounds test? • Last day to hand in missing work: • Tues. Jan. 12 • Midterm: Wed. Jan. 20 • 10:20 am-12:10 pm

31. 7 January 2010 • Objective: SWBAT name, write formulae for, and diagram ionic and covalent compounds. • Do Now: • Draw the Lewis Dot Structure for HCN.

32. Agenda • Homework answers, collect HW • Review stations • Naming ionic and covalent compounds • Formulae of ionic and covalent compounds • Properties • Lewis dot structures

33. Bonding between C and F F F C F F F F C F F C F F F F structural hybrid Lewis dot formula diagram structure =e- pair F e- C e- =covalent bond

34. Double Bond • sharing two pairs of electrons • bonds more strongly than a single bond • structural hybrid Lewis O C O O C O O C O

35. Triple Bond • Strongest N N N N N N

36. Drawing molecule diagrams • Decide how many bonds each atom makes. • The central atom is the one that makes the most bonds. • Draw with single bonds • Calculate remaining electrons • Use remaining electrons

37. HCN (hydrogen cyanide) • C=4, N=3, H=1 • HCO2- (methanoate ion) • H=1, C=4, O=2

38. Draw structural, hybrid and Lewis structures • HF • NH3 • CH4 • CF4 • NO2- • CHCl3 • NH4+ • H2CO • SeF2

39. Names and FormulaeAll Mixed Up! These are ionic OR covalent! If given the name, write the formula If given the formula, write the name

40. Length and Strength of Bonds single doubletriple longestshortest lowestenergyhighest energy

41. sometimes, a solid lattice is held together with covalent bonds • covalent network (giant covalent structures): very hard, very high melting/boiling points • Examples: diamonds and graphite (both C), SiO2