1. Announcements
Make corrections to your test. Your new grade will count as a quiz grade.
Due Monday
Missed work folder moved to 104, yellow bulletin board
Get extra help when you need it!
3rd floor office, Mondays/Thursdays 3:30-4:30 or by appointment

2. Collected today: Ions Practice worksheet
I should already have your Week 13 Homework

3. Why are we doing this? Elements in your life?
What are most things made of?
Atoms and ions combine to make compounds. (December, January…)
Compounds combine and react to make new compounds. (Next semester)

4. Bonding

5. Electronegativity
How strongly an atom attracts other electrons in a chemical bond
Increases going up a group
In lower periods, valence electrons are further from the nucleus, less “pull” from the protons
Increases going across a period
Electrons on the same energy level are more strongly “pulled” by the nucleus
Same as ionization energy!!

6. Atomic Radius Increases Atomic Radius Increases

7. Electronegativity Increases Electronegativity Increases

8. chemical bond: strong electronic attraction between atoms
decreases the potential energy of an atom; makes it more stable
only the valence electrons are involved!

9. Three Types of Bonds Bond type depends on electronegativity (e-neg)
Ionic Bond: very different e-negs.
one metal, one non-metal
Covalent Bond: both e-negs. very high
two non-metals
Metallic Bond: both e-negs. low
one or more metals

10. Non-metals
Metals

11. Anions
Cations

12. High
E-neg
Low E-neg

13. Ionic Bond
1 from here
1 from here

14. Covalent Bond
≥2 from here

15. Metallic Bond
≥1 from here

16. Ionic Bonds metal + non-metal Low e-neg. + high e-neg.
Transfer e- from one atom to another.
Form cation + anion
Ions are attracted to one another

19. sodium and chlorine Cl Na
sodium transfers its electron to chlorine

21. Ionic or Covalent Bond? Na and Cl O and F Ca and Cl Mg and Br N and O
Al and I
O and P
K and O

22. Ionic vs. Covalent Bonds: Modeling

23. Ionic Bond Vocabulary

24. Chemical formula: shows the kind and number of atoms in the smallest unit of the compound.
Ex: H2O, NaCl, C6H12O6

25. Law of Definite Proportions: In any chemical compound, the masses of the elements are in the same proportions.
Ex: If you had g of magnesium sulfide, you would always have g of magnesium and g of sulfur.
Magnesium chloride always has 1 atom of Mg to 2 atoms of chlorine.

26. Structure of Ionic Compounds:
Crystal Lattice or Array
LOTS and LOTS of ions all attracted to one another
Ex: Salt = NaCl
One Na atom for every Cl atom in a huge lattice

28. Formula unit: The formula for an ionic compound.
The lowest whole-number ratio of ions in the compound.
Ex: NaCl = 1:1 ratio of sodium to chlorine
Ex: MgCl2 = 1:2 ratio of magnesium to chlorine

29. Writing Formulae for Ionic Compounds

30. Homework

31. Polyatomic ions: most covalently bonded, but have an overall electronic charge

32. Naming Ionic Compounds
anion ending …ide
Cr(OH)3
CuF2
Ca2+ PO43-
chromium(III) hydroxide
copper(II) fluoride
Ca3(PO4)2
calcium phosphate

33. Crystal Lattice (Array)
structure of an ionic bond
each anion is surrounded by cations and vice versa

34. Announcements Missing work on spreadsheet on yellow bulletin board 
Progress Reports submitted Friday only if your grade is…
Failing
Increased by 10% or more 
Decreased by 10% or more 

35. Properties of Ionic Compounds
hard
brittle (break easily)
solid
high melting/boiling points
do not conduct electricity as solids
conduct electricity when dissolved in water (aq) or molten (melted into a liquid) - electrolyte
more soluble in water than in other solvents

37. Ionic Compunds with Transition Metals

38. Transition Metals

39. Transition Metals Transition Metals: metals in groups 3-12
Can form ions with different charges
Ex: Copper Cu+ Cu2+
Ex: Iron Fe2+ Fe3+

40. How do you know which ion is formed?
Stock System: Indicates which charge a transition metal ion has
Uses Roman Numerals to show charge
I = 1+
II = 2+
III = 3+
IV = 4+
V = 5+

41. Oxidation States (Ions) of V

42. http://www. youtube. com/watch

43. Some hints:
Stock system is ONLY used for cations that are transition metals
Cu, Fe, Hg, Pb, Sn, Cr, Mn, Co
Roman numeral comes AFTER cation.
Anions NEVER have Roman numerals.

44. Examples

45. Covalent Bonding two or more non-metals
atoms share some valence electrons (not transfer)

46. Covalent Bonding two or more non-metals
atoms share some valence electrons (not transfer)
single covalent bond: shares one pair of electrons
double: 2 pairs of e-
triple: 3 pairs of e-

47. Each e- donate by each atom
usually each atom donates (gives) one of each pair of electrons
dative covalent bond: sometimes one atom donates both electrons
Electron Pair
Shared by both atoms
Each e- donate by each atom F F

48. octet rule: usually, atoms want 8 valence e- (H, He need 2)
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)

49. Ex: C has 4 valence e- Ex: F has 7 valence e- Nitrogen?
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?

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

51. O C O O C O O C O 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

52. Triple Bond
Strongest N N N N N N

53. 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

54. HCN (hydrogen cyanide) HCO2- (methanoate ion)

55. Draw structural, hybrid and Lewis structuresHF
NH3
CH4
CF4
NO2-
CHCl3
NH4+
H2CO
SeF2

56. “…those sciences are vain and full of errors that are not born of experience, the mother of all certainty.”
Leonardo da Vinci

57. Length and Strength of Bonds
single double triple
longest shortest
lowest energy highest energy

58. Covalent Molecules covalent bonds = strong
forces between molecules = weaker
covalent molecules are easily separated from one another
soft solids
do not conduct electricity
more soluble in non-polar solvents than in water
low melting/boiling points (liquid or gas at r.t.p.)

59. 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