1. qotd How many valence electrons do Cl, and Na have?
How is an ion made?
What do you think of when you think of the word “bond”?

2. Chemical Bond

3. attraction of nuclei for electrons
Chemical Bond
attraction of nuclei for electrons
All atoms try to get a stable octet
p+ in one nucleus are attracted to e- of another atom

4. What did the atom of chlorine
say to the atom of
sodium?
You complete me.

5. Two Major Types of Bonding
Covalent Bonding
forms molecules
sharing e-
forms ionic compounds
transfer of e-
Ionic Bonding
Two Major Types of Bonding

6. One minor type of bonding
Metallic bonding
like atoms of a metal in the free state
Valence e- are mobile
Positive ions in a sea of electrons

7. It’s the mobile electrons that enable me-tals to conduct electricity!!!!!!

8. electrons are transferred between valence shells of atoms
IONic Bonding
NOT MOLECULES
electrons are transferred between valence shells of atoms
ionic compounds are made of ions
ionic compounds are called Salts or Crystals

9. [METALS ]+ [NON-METALS ]-
IONic bonding
Always formed between metals and non-metals
[METALS ]+ [NON-METALS ]-
Lost e-
Gained e-

10. NaCl CaCl2 IONic Bonding Electronegativity difference > 2.0
Look up e-neg of the atoms in the bond and subtract
NaCl
CaCl2
Compounds with polyatomic ions
NaNO3

12. qotd What kind of elements make ionic bonds?
What kind of elements make covalent bonds?
How do you make an ion with a +2 charge?
What kind of bonds make up you? Why

13. Properties of Ionic Compounds
hard 22oC
high mp temperatures
nonconductors of electricity in solid phase
good conductors in liquid phase or dissolved in water
SALTS
Crystals

14. Pairs of e- are shared between non-metal atoms
Covalent Bonding
molecules
Pairs of e- are shared between non-metal atoms
electronegativity difference
forms polyatomic ions

15. Properties of Molecular Substances
Low m.p. temp and b.p. temps
relatively soft solids compared to ionic compounds
nonconductors of electricity
Covalent
bonding

16. Chemical Bond

17. Covalent, Ionic, metallic bonding?
NH4+
Aluminum phosphate KH
KCl HF CO Co
NO2
sodium hydride Hg
H2S
sulfate
Also study
your
characteristics!

18. Drawing ionic compounds using Lewis Dot Structures
Symbol represents the KERNEL of the atom (nucleus and inner e-)
dots represent valence e-

19. [Na]+ [ Cl ]- NaCl How did we get here?
This is the finished Lewis Dot Structure
[Na]+ [ Cl ]-
How did we get here?

20. Step 1 after checking that it is IONIC
Determine which atom will be the +ion
Determine which atom will be the - ion
Step 1 after checking that it is IONIC
Write the symbol for the + ion first.
NO DOTS
Draw the e- dot diagram for the – ion
COMPLETE outer shell
Step 2
Enclose both in brackets and show each charge
Step 3

21. Draw the Lewis Diagrams
LiF
MgO
CaCl2
K2S

22. Drawing molecules using Lewis Dot Structures
Symbol represents the KERNEL of the atom (nucleus and inner e-)
dots represent valence e-

23. Always remember atoms are trying to complete their outer shell!
The number of electrons the atoms needs is the total number of bonds they can make.
Ex. … H? O? F? N? Cl? C?
one two one three one four

24. Methane CH4 How did we get here?
This is the finished Lewis dot structure
How did we get here?

25. IF the central atom has 8 valence e- surrounding it . . YOU’RE DONE!
count total valence e- involved
Step 1
connect the central atom (usually the first in the formula) to the others with single bonds
Step 2
complete valence shells of outer atoms
Step 3
add any extra e- to central atom
Step 4
IF the central atom has 8 valence e- surrounding it . . YOU’RE DONE!

26. Sometimes . . .
You only have two atoms, so there is no central atom, but follow the same rules.
Check & Share to make sure all the atoms are “happy”.
Cl Br H O N HCl

27. O O N N DOUBLE bond TRIPLE bond atoms that share two e- pairs (4 e-)
atoms that share three e- pairs (6 e-)
N N

28. Draw Lewis Dot Structures
You may represent valence electrons from different atoms with the following symbols x, ,
CO2
NH3

29. Draw the Lewis Dot Diagram for polyatomic ions
Count all valence e- needed for covalent bonding
Add or subtract other electrons based on the charge
REMEMBER!
A positive charge means it LOST electrons!!!!!

30. Draw Polyatomics
Ammonium
Sulfate

31. Types of Covalent Bonds
NON-Polar bonds
Electrons shared evenly in the bond
E-neg difference is zero
Between identical atoms
Diatomic molecules

32. Types of Covalent Bonds
Polar bond
Electrons unevenly shared
E-neg difference greater than zero but
less than 2.0
closer to more polar
more “ionic character”

33. non-polar MOLECULES
Sometimes the bonds within a molecule are polar and yet the molecule is non-polar because its shape is symmetrical. H C
Draw Lewis dot first and
see if equal on all sides

34. Polar molecules (a.k.a. Dipoles)
Not equal on all sides
Polar bond between 2 atoms makes a polar molecule
asymmetrical shape of molecule

35. H Cl + -

36. Water is asymmetrical + + H O -

37. Water is a bent moleculeH H

38. Making sense of the polar non-polar thing
BONDS Non-polar Polar Identical Different
MOLECULES
Non-polar Polar
Symmetrical Asymmetrical

39. IONIC bonds ….
Ionic bonds are so polar that the electrons are not shared but transferred between atoms forming ions!!!!!!

40. VSEPR Theory Valence Shell Electron Pair Repulsion Theory
Electron pairs orient themselves in order to minimize repulsive forces.
C. Johannesson

41. Lone pairs repel more strongly than bonding pairs!!!
VSEPR Theory
Types of e- Pairs
Bonding pairs - form bonds
Lone pairs - nonbonding e-
Lone pairs repel more strongly than bonding pairs!!!
C. Johannesson

42. 4 Shapes of molecules

43. 1. Linear (straight line)
Ball and stick model
Space filling model

44. 2. Bent
Ball and stick model
Space filling model

45. 3.Trigonal pyramid
Ball and stick model
Space filling model

46. 4.Tetrahedral
Ball and stick model
Space filling model

47. Intermolecular attractions
Attractions between molecules
van der Waals forces
Weak attractive forces between non-polar molecules
Hydrogen “bonding”
Strong attraction between special polar molecules

48. van der Waals Non-polar molecules can exist in liquid and solid phases
because van der Waals forces keep the molecules attracted to each other
Exist between CO2, CH4, CCl4, CF4, diatomics and monoatomics

49. van der Waals periodicity
increase with molecular mass.
increase with closer distance between molecules
Decreases when particles are farther away

50. Hydrogen “Bonding” Strong polar attraction
Like magnets
Occurs ONLY between H of one molecule and N, O, F of another
H “bond”

51. H is shared between
2 atoms of OXYGEN or
2 atoms of NITROGEN or
2 atoms of FLUORINE Of 2
different
molecules

52. Why does H “bonding” occur?
Nitrogen, Oxygen and Fluorine
small atoms with strong nuclear charges
powerful atoms
very high electronegativities

53. Intermolecular forces dictate chemical properties
Strong intermolecular forces cause high b.p., m.p. and slow evaporation (low vapor pressure) of a substance.

54. Which substance has the highest boiling point?HF
NH3
H2O
WHY?
Fluorine has the highest e-neg, SO
HF will experience the strongest H bonding and  needs the most energy to weaken the i.m.f. and boil