Chemical Bonding Notes: Van der Waal Forces and Water Magic

1. Warm-Up 11/2/15 (5 min) • What do you want to be when you grow up/ how do you envision your future life? • How will accountability be important in your future career/ schooling / life?

2. Announcements • No Error Analysis necessary for Lewis Dot/ Bohr Model Quiz. If you want to retake it, it will be a full retake and full replacement. Come Wed to office hours, or Thurs after school. Please sign your name on my sign up sheet. • Honors deadline for raw data was today. If you have not submitted your data, you need to inform me as to whether you are still pursuing the honors option. • We WILL have 100% project turn in. If you are behind, catch up. YOU CAN DO IT. There will be NO LATE SUBMISSIONS for the project. HARD DEADLINES for your final drafts are Tues 11/10 for the fire lab and Fri 11/13 for ink/blood labs.

3. Chemical Bonding Notes 11/2/2015 • A chemical bond is an attraction between atoms that leads to the formation of molecules. • Four of the most common types of bonds are: • 1. Van der Waal forces • 2. Hydrogen Bonds • 3. Ionic Bonds • 4. Covalent Bonds

4. 1. Van der Waal Forces • Remember that electrons move around on their orbitals. They are not perfectly, evenly spaced out, like we draw them on Bohr models.

5. 1. Van der Waal Forces • Sometimes, by chance, all of the electrons happen to be on one side of the atom. • DRAW a Bohr model for what a carbon atom would look like if all of the electrons happened to be on one side.

6. 1. Van der Waal Forces • When all of the electrons happen to be on one side of the atom, it creates a partial charge within the atom. • LABEL which side of your carbon atom you think would be negatively charged. LABEL which side of your carbon atom you think would be positively charged.

7. 1. Van der Waal Forces • When an atom has a partial charge, we label it like this.

8. 1. Van der Waal Forces This squiggle is a Greek symbol called delta. It means “partial.” means a partial negative charge. means a partial positive charge. We have to specify the partial charge because the overall atom is still neutral. (# of protons = # of electrons).

9. 1. Van der Waal Forces When the electrons are not evenly distributed ( they’re mostly on one side), it creates an instantaneous dipole. Dipole = 2 poles. One positive pole, and one negative pole. (similar to a magnet.)

10. 1. Van der Waal forces • When one atom has a dipole, it can cause neighboring atoms to form dipoles. This is called an induced dipole.

11. 1. Van der Waal Forces • Van der Waal forces are the weak bonds that occur between atoms when the negative dipole of one atom is attracted to the positive dipole of another atom.

12. 1. Van der Waal Forces • Which atoms do you think form stronger dipoles—atoms with lots of electrons, or atoms with not very many electrons?

13. 1. Van der Waal Forces • If an atom has lots of electrons, it can form a stronger dipole, which makes the Van der Waal forces stronger. This makes the bond between 2 atoms harder to break.

14. Remember… • Van der Waal forces are responsible for antigens binding to antibodies! (Relevant to blood lab intro)

15. Warm-Up 11/3/15 • What causes Van der Waal forces to occur? • Bonus: Which noble gas do you think has a higher boiling point: helium, or radon? Explain why.

16. Upcoming Things! • We will have project work time tomorrow. • FIRE LAB peer reviews are due Thurs. • INK/BLOOD LAB complete APA rough draft due Fri. • Bohr Model/Lewis Dot Retake tomorrow during OH, or Thurs. after school. SIGN UP on my sheet, please!

17. Instructions for Peer Review 1. GIVE HELPFUL FEEDBACK: • Look at collaboration rubric (on project info tab of my DP). • You need to read 2 people’s full rough drafts. Make comments and suggest edits directly on their google doc. Score them on hard copies of the content and literacy rubrics. 2. RATE THE FEEDBACK YOU RECEIVED: • When you receive your feedback from a peer, score your peer on how helpful their feedback was (1-4), using the collaboration rubric. • Write “(my name)’s score for (person who graded me’s name)” on the top of the collaboration rubric. Place the completed collaboration rubric in YOUR PARTNER’s file folder (by the literacy wall). I will check them there. Do not remove any collaboration rubrics from your folder, or you will receive a 1 for collaboration.

18. Water Magic! • Fill your container most of the way with water. When the water is almost to the top, add additional water drops one by one with a pipette. Observe what happens. Compare what happens in your container to what happens in other containers.

19. Woah! Why did this happen? • Water sticks to itself via HYDROGEN BONDS!

20. Hydrogen Bond Videos • https://www.youtube.com/watch?v=Jkxad9yMUWo • https://www.youtube.com/watch?v=HVT3Y3_gHGg

21. Binder Check!

22. Question 1 • 1. What word went in the second to last blank on yesterday’s hydrogen bond video notes?

23. Question 2 • 2. Look at Part 1 Analysis of the Periodic Trends in Reactivity Lab. What sentence is written in bold font under #1?

24. Question 3 • 3. Look at your Project 2 Murder Mystery Brief. What is the very last word on the “Formal Lab Report Guidelines” side?

25. Question 4 • 4. What was the date on your Electronegativity Notes?

26. Question 5 • 5. What element was the answer to the Warm Up on 10/6/15?

27. Question 6 • 6. What vocabulary word corresponds to letter D from the word bank on the Matter and Atomic Structure Unit Assessment?

28. Question 7 • 7. What date was on your formal APA lab report for the Murder Lab?

29. Question 8 • 8. What was the independent variable on the warm-up from 8/31?

30. Question 9 • 9. What was the warm up on 9/10/15 about?

31. Question 10 • 10. Draw the picture that corresponds to the first sentence of the summary that you wrote on 10/16.

32. Question 11 • 11. What word is written in bold and italic font under #1 on the “Atomic Radius: Data Collection” worksheet?

33. Question 12 • 12. How many points did you need to pass the Level 2 portion of the Dimensional Analysis Quiz?

34. Question 13 • 13. Look at your “Electronegativity HW.” What 2 elements are under letter f of #6?

35. Warm Up 11/9/15 How are the strength of Van der Waal forces in a compound and the compound’s boiling point related? Explain why.

36. Announcements • Happy Monday! Life is great this week! Wed= no school. Thank you, veterans! Fri= 9th grade TED talks • Project 2 peer reviews due TOMORROW at 9AM. Give a collaboration score (1-4) for the person who reviewed your lab. Put their score in THEIR folder by the scientific literacy wall. • Fire lab final draft due TOMORROW! Blood and ink final drafts due FRIDAY at 9AM. • Honors APA write up due Thursday

37. Warm Up 11/10/15 • What is electronegativity? • What group # are the Noble Gases in? Why are the Noble Gases special?

38. Ionic and Covalent Bond Notes 11/10/15 • Atoms give, take, or share electrons to become stable like a noble gas. • Reminder—These are the noble gases. They have 2, 10, 18, 36, 54, and 86 electrons.

39. Review… • The bonds we learned so far are ______________ and ________________. • These are both intermolecular forces, which means that they are forces of attraction or repulsion between neighboring particles (i.e. between multiple bonds of water)

40. Today… • The next two bonds we will learn are ionic bonds and covalent bonds. • These are both STRONG intramolecular forces, which means that they hold atoms together to make a molecule.

41. For example… • A sodium atom, Na, is unstable with its normal 11 electrons. If it loses 1 e-, it becomes stable like the noble gas Neon, with 10 e-.

42. Question… • A Cl atom is unstable with 17 electrons. What noble gas configuration is it closest to? Does it need to gain or lose electrons to become like a noble gas?

43. Ionic Bond • In an ionic bond, an atom that has lost electronsbonds with one (or several) atoms that have gained electrons. • Ionic bonds form between a metal and a non-metal. (like #1-3 of your gummy bear models)

44. Example When Cl steals Na’s electron, it gains a -1 net charge, becoming an anion. Since Na loses an electron, it gains a +1 charge and becomes a cation. The opposite charges of the ions attract, and this attraction holds the molecule together. What compound is being formed?

45. Why? • The nonmetal is able to steal electrons from the metal because it has a much higher electronegativity. It is like a tug of war that the nonmetal always wins.

46. Covalent Bond Covalent Bond: • Electrons are shared between two or more non-metal atoms. • (like #4-6 of your gummy bear models)

47. How Covalent Bonds Form…

48. Covalent bonds allow each individual water molecule to form

49. Why? • The atoms in a covalent bond cannot steal electrons from each other because their electronegativities are too similar. It is like a tug of war that neither side can win. Instead, the electrons get stuck in the middle of the atoms, and they share.