11/11/2016
Predicting Bond Types
Using Electronegativity and Rule of Thumb
Electronegativity – Page 7
• The type of bond can be predicted by subtracting electronegativity
values.
1. Find the electronegativity values for each element.
2. Subtract the lesser value from the higher value.
3. Find the difference on the chart; convert to a bond type.
Difference
Bond Type
X ≤ 0.3
Non-Polar Covalent
0.3 ≤ X ≤ 1.7
Polar Covalent
X ≥ 1.7
Ionic
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Values on Page 6
Learning Check – Page 7
Use the electronegativity difference to identify the type of bond between the
following:
nonpolar covalent (NP), polar covalent (P), or ionic (I).
1.
2.
3.
4.
5.
Ca, Br
O, H
C, H
Na, Cl
S, O
6. N, N
4
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Rule of Thumb – Page 8
• Based on elements in compound.
•
•
•
•
•
•
Active Metal (S-block) + Non metal  Ionic Bond
Transition Metal (D and F blocks) + Non metal  Ionic or Covalent
Metal + Metal  Metallic
Two different Non-metals  Polar Covalent
Two same Non- Metals  Non-Polar Covalent
Noble gas + any element  No bond
Elements
Au and I
Ca and F
P and Br
Ag and Cl
Ti and O
Predict using
Rule of Thumb
Au = TM
I = NM
Ca = M
F = NM
P = NM
Br = NM
Ag = TM
Cl = NM
Ti = TM
O = NM
Predict based on
Electronegativity
values
(see page 5)
Au = 2.4
I = 2.5
Ca = 1.0
F = 4.0
P = 2.1
Br = 2.8
Ag = 1.9
Cl = 3.0
Ti = 1.5
O = 3.5
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