1. 4/12 Bell Work
Nothing is particularly hard if you divide it into small jobs.
-- Henry Ford
Who is Henry Ford, and what did he mean?

2. 4/12 Schedule Finish Tests if needed
Use notes, Periodic Table, calculator, snake chart, and Review sheet
Notes online “Chemical Formulas and Compounds”
Ch 6.1 “Compounds and Molecules”
Assignments:
1. Concept Review Ch 6 “Compounds” - TBA

3. Unit : Chemical Formulas & Compounds
Ch 6 Objectives:
Correctly name and write formulas for compounds.
Compare/contrast different bond types.

4. Ch 6.1 “Compounds and Molecules”
Objectives
Describe chemical bonds.
Model compound structure in different ways.
Explain what causes compound properties.

5. Chemical Structure Intro
Study the models of the water molecule, H2O, and the carbon dioxide molecule, CO2.
1. Name some similarities between the molecules of H2O and CO2.
2. How are the molecules different?

6. Chemical Bonds Bonds Compounds have very specific formulas
Hold atoms or ions together in compounds
Compounds have very specific formulas
H20 (water) and H2O2 (peroxide) have very different properties.

7. Chemical Structure Multiple Structure Models
Chemical Structure: the arrangement of atoms in a substance
Some models represent bond lengths and angles.
bond length: the average distance between the nuclei of two bonded atoms
bond angle: the angle formed by two bonds to the same atom, shows the shape of the compound

8. Bond Length Model
Ball and Stick Model
Space filled model

9. Chemical Structure Ball-and-stick model, Atoms are balls.
Bonds holding atoms together are sticks.
Structural formulas
Chemical symbols represent atoms.
Space-filling models
Show the space occupied by atoms.

10. Chemical Structure Flexible Bonds
bend, stretch, and rotate without breaking.
Could be represented by flexible springs.
Most reported bond lengths are average distances.
There are different kinds of bonds
All atoms are vibrating because of thermal energy

11. Structure Affects Properties?
The chemical structure of a compound determines its properties.

12. Structure Affects Properties?
Network structures make strong solids.
Example: Quartz, SiO2 is made of silicon and oxygen atoms.
The atoms are bonded in a strong, rigid structure (aka crystals).
Titanium flame aura quartz

13. Structure Affects Properties?
Ionic Networks
The strong attractions between the oppositely charged ions gives these compounds high melting points and high boiling points.
EX: Table salt—sodium chloride—is a tightly packed repeating network of positive Na+ ions and Cl- ions.

14. Structure Affects Properties?
Sodium chloride
Melting point: 801o C or 1474o F
Boiling point: 1413o C or 2575o F
Sodium chloride crystal

15. Structure Affects Properties?
Some compounds are molecules.
Can be solids, liquids, or gases.
The strength of attractions between molecules varies.
High melting and boiling points = strong attractions
Low mp and bp = weak attractions

16. Structure Affects Properties?
Sucrose (table sugar)
Melting point: breaks down at 186o C
Boiling point: NA
Sucrose crystal

17. Water Bonding Hydrogen Bonding H is attracted to O, N, and F
EX: Water.
Not as strong as the bonds holding the molecule together.

18. 4/13 Bell Work Solve the word puzzles.
Working overtime, do without, teddy bear

19. 4/13 Schedule Compound Properties Lab Work
Notes Ch 6.1 “Compounds and Molecules”
Concept Review Ch 6 “Compounds”
Assignments:
1. Concept Review Ch 6 “Compounds” - TBA

20. Chemical Models Review
Identify which model of methane is the:
Ball-and-stick model
Structural formulas
Space-filling models

21. Bunsen Burner Procedure
Inspect burner and tubing for rust or cracks.
Close air hole on burner and attach tubing to gas jet.
Turn gas on until you hear a faint hiss. Quickly use striker to light burner. If it doesn’t light in 2-3 tries, turn off gas and wait for it to dissipate before trying again.
Adjust flame as needed using the metal sleeve, usually looking for a double cone of blue flame.
Turn off gas and carefully disconnect tubing.

22. Compound Properties Lab
WEAR. YOUR. GOGGLES!!
Be careful… hot!
Read the lab carefully!
Refer Ch 6.1 “Compounds and Molecules” book/notes and lab to answer questions.
Clean Up
Foil and used chemicals in lab garbage.
Disconnect Bunsen burners.
Materials back where you found them.

23. 4/18 Bell Work
A railroad line has a double track, except in a tunnel where there isn’t enough room. A train goes in the tunnel in one direction. Another train enters in the opposite direction. Both trains are traveling very fast, yet they do not collide.
How can this be?
Enter at different times

24. 4/18 Schedule Notes Ch 6.2 “Ionic and Covalent Bonding” Work
Concept Review Ch 6 “Compounds”
Finish Compound Properties Lab - TODAY
Assignments:
1. Concept Review Ch 6 “Compounds” - TBA

25. Ch 6.2 “Ionic and Covalent Bonding”
Objectives
Explain why atoms form bonds.
Compare and contrast ionic, covalent, and metallic bonds.
Describe how polyatomic ions are similar to other ions.

26. DTC: “Chemical Bonds”
Watch the video clip as Paige and Dexter demonstrate how chemical bonds are formed. Be able to answer the questions below.
In ionic bonds, electrons are __________________.
What is the difference between an anion and a cation?
Valence electrons are _____________ in covalent bonds.

27. Bonding Preview
An ionic bond is a chemical bond that is usually formed between a metal and a nonmetal. In an ionic bond, electrons are gained or lost. A covalent bond is a bond that is usually formed between two nonmetals. These atoms share electrons.

28. Bonding Preview What kind of bond would join two oxygen atoms?
What kind of bond would join sodium atoms with chlorine atoms to form salt?
What kind of bond would join a hydrogen atom with an oxygen atom?

29. Why Do Chemical Bonds Form?
Bonding Rationale and Type
Generally, atoms join so each has a stable electron configuration.
“Noble gas envy”
Usually 8 electrons
2 basic kinds of chemical bonding:
ionic bonding
covalent bonding

30. Comparing Ionic and Covalent Bonds

31. Ionic Bonds Ionic bonds are formed by the transfer of electrons.
Atoms tend to form ionic bonds when one atom has more attraction for electrons than the other.
Made of ions or metal and a nonmetal
Ionic compounds form of networks.
A formula unit is the smallest ratio of ions in ionic compounds.

32. Ionic Bonds

33. Ionic Bonds This is a calcium fluoride crystal.
Use the formula unit to predict how to write its chemical formula.

34. Polyatomic Ions Polyatomic Ions: an ion made of two or more atoms
Function and travel as a unit
Common examples
hydroxide – OH-
carbonate -- CO3 2-
ammonium – NH4 +
Use parenthesis if you need to write more than 1
Ex: the formula for ammonium sulfate is written as (NH4)2SO4, not N2H8SO4.

35. Polyatomic Ions
Usually names of polyatomic anions relate to their oxygen content.
An -ate ending names the ion with more oxygen atoms.
Examples: sulfate (SO42–), nitrate (NO3–), chlorate (ClO3–)
An -ite ending names the ion with fewer oxygen atoms.
Examples: sulfite (SO32–), nitrite (NO2–), chlorite (ClO2–)

36. Polyatomic Ions

37. Covalent Bonds Covalent bonds share…
covalent bond: a bond formed when atoms share one or more pairs of electrons.
Networks of bonded atoms, such as silicon dioxide, are also covalently bonded.
Usually form between nonmetal atoms
Common covalent compounds: water, sugar, and nitrous oxide.

38. Covalent Bonds Covalent compounds can be solids, liquids, or gases.
In a chlorine molecule, Cl2, the atoms share two electrons.
One pair = single covalent bond.
5th stopped here

39. Covalent Bonds Atoms may share more than one pair of electrons.
Two pairs form a double covalent bond.
4 electrons
Stronger and shorter than single bonds
aka double bonds
Three pairs of shared electrons form a triple covalent bond.
6 electrons
Stronger and shorter than double bonds

40. Multiple Bonds

41. 4/19 Bell Work
How many numbers between are multiples both of 2 and 3? 16
33 multiples of 3, half are even

42. 4/19 Schedule Notes Ch 6.2 “Ionic and Covalent Bonding”
Lewis Structure Wksht due FRIDAY
Work
Concept Review Ch 6 “Compounds”
Finish Compound Properties Lab - LATE
Assignments:
Concept Review Ch 6 “Compounds” – TBA
Compound Properties Lab – LATE
Lewis Structure Wksht - FRIDAY

43. Predicting Bonds: Lewis Structures
Lewis Structures predict how atoms are connected in compounds.
Find your element on the periodic table.
Determine the number of valence electrons.
This is how many electrons you will draw.

44. Groups - Review Group 1 = 1 electron Group 8 = 8 electrons
Except for He, it has 2 electrons
Group 2 = 2 electrons
3, 4, 5, 6, 7
The electrons in the outer shell are called “valence electrons”

45. Lewis Structures Find out which group your element is in.
This tells you the number of valence electrons.

46. C Lewis Structures Write the element symbol.
Carbon is in the 4th group, so it has 4 valence electrons.
Starting at the right, draw 4 electron dots, counter- clockwise around the element symbol.
Only pair up if there are more than 4. C

47. Lewis Structures
Try these elements on your own. H P Ca Ar Cl Al C

49. Lewis Structures of Compounds
Figuring out Structure of Compounds
The goal of the Lewis structure is to have all atoms stable (usually 8).
Exceptions: H only wants 2 e-,B wants 6, P can have 10, S can have 12
Write the chemical formula, and count the total # of valence electrons.
This is the amount of electrons allowed in the Lewis Structure
These electrons can be placed anywhere in the structure and don’t belong to any specific atom.

50. Lewis Structures of Compounds
Figuring out Structure of Compounds Arrange the atoms around each other, sharing electrons as needed Put the dot structure in brackets and include charge if it is a polyatomic ion.
Water vs Hydroxide ion

51. Lewis Structures of Compounds
Hints: a) The least electronegative atom typically goes in the center - usually C b) Hydrogen is terminal (at the end b/c it only can form 1 bond) 3. Put in electrons (dots) around the atoms to satisfy the octet of atoms 4. Check to see that you have the same # e-s as in step 1, if not, rearrange the # e-s and/or atoms.

52. Lewis Structure Examples
H2O
CCl4
BI3

53. 4/20 Bell Work
Two hours ago it was as long after 1 o’clock in the afternoon as it was before 1 o’clock in the morning.
What time is it now?
9 o’clock, 1+6 = 7+2 = 9

54. 4/20 Schedule Notes Ch 6.2 Review Lewis Structures Work
Concept Review Ch 6 “Compounds”
Finish Compound Properties Lab – LATE
Lewis Structure Wksht due FRIDAY
Assignments:
Concept Review Ch 6 “Compounds” – TBA
Compound Properties Lab – LATE
Lewis Structure Wksht - FRIDAY

55. Covalent Bonds Atoms do not always share electrons equally.
Nonpolar covalent bonds: electrons are shared equally
Polar covalent bond: unequal sharing of electrons.
Coordinate covalent bonds: both shared electrons come from one element
Electrons tend to be more attracted to atoms farther to the right and closer to the top of the periodic table.
Fl most, Fr least

56. Metallic Bonds Distinctive Metal Properties
Metals are flexible and conduct electricity because their atoms and electrons can move freely throughout a metal’s packed structure.
metallic bond: a bond formed by the attraction between positively charged metal ions and the electrons around them
Metal cations in a “sea” of electrons.

57. Review Lewis Structures
ClO31- (expanded octet or coordinate covalent)
Number e- =
Brackets and charge?
HCN (multiple bonds)
ClF3 (expanded octet)