1. Chemical bonds are invisible forces that hold atoms together in compounds. They form when atoms undergo changes and combine with each other. 2. There are two main types of chemical bonds - ionic bonds and covalent bonds. Ionic bonds involve the transfer of electrons between atoms to form ions, while covalent bonds involve the sharing of electrons between atoms. 3. The shape and properties of molecules can be predicted using Lewis structures, the valence shell electron pair repulsion (VSEPR) model, and by determining the hybridization of the atoms' orbitals. This allows for determining important characteristics like molecular geometry.

1. ATOMS ALWAYS UNDERGO CHANGE AND IN
DOING SO, THEY COMBINE WITH EACH
OTHER, AND HOLD TO EACH OTHER USING
AN INVISIBLE FORCE CALLED A CHEMICAL
BOND.

2. Chemical Bond – invisible force that
hold atoms together in a compound.
Rationale : stability : Octet Rule and
or Rule of 2

3. KINDS Results FORMS STRENGHT
E’s are transferred from a
Metal to a non metal
With formation
Of ions
Electrostatic
Attraction
Between
Cation & anion
E’s are shared between
Several non metals
Without
Formation of
ions
ionic
covalent
Attraction between
The + charged nucleus
And the - electron
Clouds of the bond &
Attraction involving
The opposite spins of
electrons

4. Atoms Lewis
symbol
Formation of
Pertinent Bond
Formula
iA Na
VIIA Cl
Transfer of
electrons
Na
1
Cl
NaClNa
Cl

5. IIA Ca
IIIA N
Transfer of
electrons
Ca
N Ca
+2
N
-3
_______________
+2 -3
LCM= 6
__3________2______
+6 -6
Ca3N2

6. IA H
VIIA Cl
Sharing of
electrons HCl
H
Cl
Cl
H H
Cl

7. IA H
IVA C
Sharing of
electrons CH4
H
C
C
H
H
H
H C H
H
H
H

8. • In bonding, compound formation,
•
• total positive charge = total negative charge
• Total electropositive charge = total electronegative
charge

9. BOND POLARITY
• Arises whenever atoms share their electrons
unequally that is whenever they have
different electronegativities

10. Kinds of chemical bonds
Basis of sharing of electrons
• Non polar covalent
bond
– atoms share their
electrons equally;
atoms have equivalent
electronegativities
• Polar covalent bond-
• atoms share their
electrons non equally;
atoms have different
electronegativities

11. • Rule :Basis of electronegativity difference
(END)
1. If END range is 0 to 0.4 non polar covalent
bond
2. If END range is 0.5 to 1.7 to 1.9 – polar
covalent bond
3. If END range is >0.5 to 1.7 to 1.9 – ionic bond
•

13. THEORIES OF COVALENT BONDING
1. Valence Bond Theory- Atoms contain orbitals (
with spatial orientations and shapes) that will
overlap maximally to form covalent bonds
2. Hybridization Theory-
Hybridization- way of trying to modify the
orbital model of an atom to explain the
existence of bonds that are equivalent
Mixing of electrons to form hybrid orbitals

23. Atoms that show multiple covalency numbers
will hybridize
• Covalency Number – number of unpaired
electrons
• -dictates the number of possible bonds to be
formed

24. LEWIS SYMBOL COVALENCY
NUMBER
NUMBER OF
FORMED
BONDS
HYBRIDIZED ?
H 1
1 NO

25. LEWIS SYMBOL COVALENCY
NUMBER
NUMBER OF
FORMED
BONDS
HYBRIDIZED ?
Cl
1 1
NO

26. LEWIS SYMBOL COVALENCY
NUMBER
NUMBER OF
FORMED
BONDS
HYBRIDIZED ?
C
4 4
YES

27. LEWIS SYMBOL COVALENCY
NUMBER
NUMBER OF
FORMED
BONDS
HYBRIDIZED ?
N
3
3
YES

28. LEWIS SYMBOL COVALENCY
NUMBER
NUMBER OF
FORMED
BONDS
HYBRIDIZED ?
O
2 2 YES

29. Hybrids Orbitals
involved
Number
of
hybrids
Number
of pure
orbitals
Name of
hybrid
Angle of
repulsion
among
hybrids
Angle of
repulsion
between
hybrid and
pure
orbitals
Sp3 S p p
p
4 0 tetrahedra
l
1090
Sp2 S p p 3 1, (p
orbital)
Trigonal
planar
1200 900
sp S p 2 2 ( 2 p
orbitals)
digonal 1800 900

30. • Hybridization Rule :
• Number of hybrid orbitals formed =number
of pure atomic orbitals used

31. To predict the type of hybrid of an Atom:
• Single bonds – sp3
• Double bonds – sp2
• Triple bonds - sp

32. • For Carbon:
•
• If C is bonded to 4 other atoms ; sp3
• If C is bonded to 3 other atoms ; sp2
• If C is bonded to 2 other atoms ; sp

33. • For N:
• If N is bonded to an sp3 C ; sp3 N
• If N is bonded to an sp2 C; sp2 N
• If N is bonded to an sp C; sp N

34. • For O
• If O is bonded to an sp3 C; sp3 O
• If O is bonded to an sp2 C; sp2 O

35. CH3 H
CH2 = CH2
CH CH
1
2
3

36. CH3 C= O
O
H
CH3 C= O
O
CH3
sp2
sp2
sp2
sp3
sp2

37. CH2
H
4
5

38. CH3 N
C
N
C
O
O
CH3

39. CH3 N
C
N
C
O
O
CH3
sp2
sp2
p
p
sp2
sp2

40. UNIQUE PROPERTIES OF WATER
• Many of the unusual properties of water are a
result of its chemistry
• 1. is a polar molecule, with a positively and
negatively areas. It causes H- bonding. Each
water molecule can form 4 H-bonds.
• 2. is a bent molecule

41. Properties Environmental Impact
High boiling point
High heat capacity Allows ocean to have a moderating
influence on climate particularly along
coastal areas
Ocean does not experience the wide
temperature fluctuations that are
common on land
High heat of vaporization As water evaporates it carries the heat
with it into the air thus has a cooling
effect. The body is cooled when
perspiration evaporates from the skin
Less dense at temperature below 4oC (ice) Ice floats on denser liquid water . Because
of this water freezes from the top down
rather than from the bottom up so that
aquatic life can survive beneath a frozen
surface

42. O
H
H
O
H
H
O
H
H
O
H
H
O
H
H
O
H
H
O
H
H
O
H
H

43. PREDICTINGMOLECULAR GEOMETRY

44. PREDICTING MOLECULAR GEOMETRY
uses
Lewis Formula Valence Shell
Electron Pair
Repulsion
Steps; (VSEPR)
1. determine the skeleton structure
of the molecule
2. be sure to count that the total
number of dots is equal to the
total number of valence electrons
3. surround each atom with 8 dots;
except H, with 2 dots

45. Skeleton structure : (Which atom is
bonded to which ?)
ligands Central atom
Atom with lower group number
Atomwith lower electronegativity
Atom with higher period number : when
the atoms have the same group numbers
NF3
Rationale
It needs more e’s to attain octetN F
F
F
N VA F VIIA
EN 3 EN 4

46. Atom with higher period number :CENTER ATOM
when the atoms have the same group numbers :
SO3
period 3S VI A
O VIA period 2
S O
O
O
Cl F3

47. For molecules add up the valence
electrons of the atoms.
In the NF3 , N has five e’s and each F has
7 e’s
(Recall that the number of valence
electrons equals the A- group number
For polyatomic ion, add 1 e ‘ for each negative
charge, or substract e’ for each positive charge

53. VSEPR
E’ pair around
Central atom
Minimum
Repulsion
LONE
PAIR
Directional
property
BOND
PAIR
6
2
3
4
5
linear
Trigonal planar
tetrahedral
Trigonal bipyramid
octhedral
suggests Should
exert
Can be
with without
when
modifies
Repel in a
way to
form

55. 3 electron groups
Trigonal planar
arrangement
Trigonal planar V shape
2 molecular shapes
is
has
when
All 3 bond pairs 1 lone pair
2 bond pairs

56. 4 electron groups
Tetrahedral
arrangement
3 molecular shapes
is
has
Tetrahedral V shape
when
pyramidal
All 4 bond pairs
1 lone pair
3 bond pairs
2 lone pairs
2 bond pairs

57. 5 electron groups
Trigonal
bipyramidal
arrangement
4 molecular shapes
is
has
Trigonal
bipyramidal
linear
when
T- shapeSee- saw
All 5 bond
pairs
1 lone pair
4 bond pairs
2 lone pairs
3 bond pairs
3 lone pairs
2 bond pairs

58. 6 electron groups
Octahedral
arrangement
3 molecular
shapes
is
has
octahedral Square planar
when
Square pyramidal
All 6 bond pairs
1 lone pair
5 bond pairs
2 lone pairs
4 bond pairs

59. N HH
H
109.5
107
104
Electron pair repulsions cause deviations from ideal bond angle s in the order
Lone pair lone
pair repulsion
Lone pair bond
pair repulsion
Bond pair bond
pair repulsion>>
O
HH

60. equatorial
equatorial
axialaxial
lying in a plane lying in a plane
Lying above and below of plane Lying above and below of plane
Five and six electron groups In a molecule with this arrangement , there
are 2 types of positions for sorrounding
electron groups , and 2 ideal bond angles
120
90
90
90
LONE PAIRS
OCCUPY
EQUATORIAL
POSITIONS
The greater the
bond angle , the
weaker the
repulsionRationale

61. Complete the Table
molecule Lewis Structure Molecular shape
Orbital
hybridizatiion
of the central
atom
P Cl
Cl
Cl
Cl
PCl4
+
VA VII A
tetrahedral
sp3
all 4 bond pairs
P Cl
Cl
Cl
Cl
5X1 =5
7X4= 28
------------
33 -1=32 - 8 = 24 -24 =0

62. molecule Lewis structure Molecular
geometry
Orbital
hybridization
Of the central
atom
NO2
-
VA VIA
N OO
BENT SP2
N OO
5X1 =5
6X2 = 12
---------------
17 +1 = 18 -4 = 14 -12 = 2 -2= 0

63. molecule Lewis structure Molecular
geometry
Orbital
hybridization
Of the central
atom
NF3
VA VII A
N F
F
F
5 X1 = 5
7 X 3 = 21
--------------
26 - 6 = 20 - 18 = 2
Pyramidal
sp3N F
F
F