1. TYPES OF CHEMICAL BONDS
IONIC BONDS
COVALENT BONDS
HYDROGEN BONDS
METALLIC BONDS

2. IONIC BONDING

3. IONIC BONDING When an atom of a nonmetal takes one or more electrons
from an atom of a metal
so both atoms end up with
eight valence electrons

4. IONIC BONDING IS THE COMPOUND AN IONIC COMPOUND? Mg N 3 2 NONMETAL
SUBSCRIPTS

5. IONIC BOND FORMATION Non-Metal Metal
Neutral atoms come near each other. Electron(s) are transferred from the Metal atom to the Non-metal atom. They stick together because of electrostatic forces, like magnets.

6. Metals will tend to lose electrons and become
IONIC BONDING
Metals will tend to lose electrons and become
POSITIVE CATIONS = Na
11 p
10 e + -
to become sodium ion + -
11 p
11 e Na
Normal sodium atom - 1e
loses one electron

7. Nonmetals will tend to gain electrons and become
IONIC BONDING
Nonmetals will tend to gain electrons and become
NEGATIVE ANIONS
17 p
17 e + - Cl
Normal chlorine atom = Cl
17 p
18 e + -
to become a chloride ion + 1e -
gains an electron

8. Properties of Ionic Compounds
Crystalline structure.
A regular repeating arrangement of ions in the solid.
Ions are strongly bonded.
Structure is rigid.
High melting points- because of strong forces between ions.

9. Crystalline structure
The POSITIVE CATIONS stick to the NEGATIVE ANIONS, like a magnet.

10. Do they Conduct? Conducting electricity is allowing charges to move.
In a solid, the ions are locked in place.
Ionic solids are insulators.
When melted, the ions can move around.
Melted ionic compounds conduct.
Melting points always above 800ºC.
Dissolved in water they conduct.

11. Ionic solids are brittle+ -

12. Ionic solids are brittle
Strong Repulsion breaks crystal apart. + - + - + - + -

13. COVALENT BONDING

14. COVALENT BOND FORMATION
When one nonmetal shares one or more electrons with an atom of another nonmetal so both atoms end up with eight valence electrons

15. COVALENT BONDING IS THE COMPOUND A COVALENT COMPOUND? C O 2 NONMETAL
YES since it is made of only nonmetal elements

16. Covalent bonding
Fluorine has seven valence electrons F

17. F F Covalent bonding Fluorine has seven valence electrons
A second atom also has seven F F

18. F F Covalent bonding Fluorine has seven valence electrons
A second atom also has seven
By sharing electrons F F

19. F F Covalent bonding Fluorine has seven valence electrons
A second atom also has seven
By sharing electrons F F

20. F F Covalent bonding Fluorine has seven valence electrons
A second atom also has seven
By sharing electrons F F

21. F F Covalent bonding Fluorine has seven valence electrons
A second atom also has seven
By sharing electrons F F

22. F F Covalent bonding Fluorine has seven valence electrons
A second atom also has seven
By sharing electrons F F

23. F F Covalent bonding Fluorine has seven valence electrons
A second atom also has seven
By sharing electrons
Both end with full orbitals F F

24. F F Covalent bonding Fluorine has seven valence electrons
A second atom also has seven
By sharing electrons
Both end with full orbitals F F
8 Valence electrons

25. F F Covalent bonding Fluorine has seven valence electrons
A second atom also has seven
By sharing electrons
Both end with full orbitals F F
8 Valence electrons

26. Single Covalent Bond A sharing of two valence electrons.
Only nonmetals and Hydrogen.
Different from an ionic bond because they actually form molecules.
Two specific atoms are joined.
In an ionic solid you can’t tell where the electrons came from

27. H O Water Each hydrogen has 1 valence electron
Each hydrogen wants 1 more
The oxygen has 6 valence electrons
The oxygen wants 2 more
They share to make each other happy H O

28. H O Water Put the pieces together The first hydrogen is happy
The oxygen still wants one more H O

29. H O H Water The second hydrogen attaches
Every atom has full energy levels H O H

30. Two types of covalent bonds:
Sigma bonds: represented by the symbol two orbitals with a DIRECT overlay (so it falls DIRECTLY between the nuclei of the atoms in the bond)

31. Two types of bonds
Another view of sigma bonds (showing electron clouds):

32. Two types of covalent bonds:
Pi bonds, represented by the symbol
two lobes of one involved atomic orbital overlap two lobes of the other involved atomic orbital.

33. Two types of covalent bonds
So single bonds (or the FIRST bond formed) is a bond, and the second and/or third are always bonds

34. Coordinate covalent bond
Other examples:

35. Polar Molecules Molecules with a positive and a negative end
Requires two things to be true
The molecule must contain polar bonds
This can be determined from differences in electronegativity.
Symmetry can not cancel out the effects of the polar bonds.
Must determine geometry first.

36. Is it polar? HF
H2O
NH3
CCl4
CO2

37. Intermolecular Forces
What holds molecules to each other

38. Intermolecular Forces
They are what make solid and liquid molecular compounds possible.
The weakest are called van der Waal’s forces - there are two kinds
Dispersion forces
Dipole Interactions
depend on the number of electrons
more electrons stronger forces
Bigger molecules

39. Dispersion forces
When electrons temporarily ‘clump’ in one part of a molecule
Results in a temporary attractive force from a temporary dipole

40. Dispersion Forces Also called London Forces or Van der Waals forces
The larger the molecule, the greater the additive effect

41. Dispersion Forces
This is why gasoline is a liquid at room temperature, but methane is a gas

42. Dipole interactions Fluorine is a gas Bromine is a liquid
Depend on the number of electrons
More electrons stronger forces
Bigger molecules more electrons
Fluorine is a gas
Bromine is a liquid
Iodine is a solid

43. Dipole interactions H F d+ d- H F d+ d-
Occur when polar molecules are attracted to each other.
Slightly stronger than dispersion forces.
Opposites attract but not completely hooked like in ionic solids.
H F
d+ d-
H F
d+ d-

44. Dipole Interactions
d+ d-
d+ d-
d+ d-
d+ d-
d+ d-
d+ d-
d+ d-
d+ d-

45. Hydrogen bonding
Are the attractive force caused by hydrogen bonded to F, O, or N.
F, O, and N are very electronegative so it is a very strong dipole.
The hydrogen partially share with the lone pair in the molecule next to it.
The strongest of the intermolecular forces.

46. Hydrogen Bonding H O d+ d- H O d+ d-

47. Hydrogen bonding H O H O H O H O H O H O H O

48. Metallic Bonds Metals hold onto their valence electrons very weakly.
Think of them as positive ions floating in a sea of electrons.

49. Sea of Electrons
Valence electrons are free to move through the solid.
Metals conduct electricity. +

50. Hammered into shape (bend). Ductile - drawn into wires.
Metals are Malleable
Hammered into shape (bend).
Ductile - drawn into wires.

51. Malleable +

52. Malleable
Electrons allow atoms to slide by. + + + + + + + + + + + +