Shows molecular shapes and how to predict them. Also,how shape effects molecular properties. **More good stuff available at: www.wsautter.com and http://www.youtube.com/results?search_query=wnsautter&aq=f

1. Copyright Sautter 2015

2. MOLECULAR GEOMETRY (SHAPES)
• SHAPES OF VARIOUS MOLECULES DEPEND ON
THE BONDING TYPE, ORBITAL HYBRIDIZATIONS
AND THE NUMBER OF BONDS THAT OCCUR IN THE
BONDING ATOMS OF THE MOLECULE.
• THREE FUNDAMENTAL RULES RELATE TO THE
POSITIONING OF ATOMS IN MOLECULES.
• (1) BONDED ATOMS TEND TO MOVE AS CLOSE AS
POSSIBLE TO THE CENTRAL ATOM OF A
MOLECULE
• (2) ATOMS WHICH ARE BONDED TO THE CENTRAL
ATOM TEND TO STAY AS FAR FROM EACHOTHER
AS POSSIBLE.
• (3) LONE ELECTRON PAIRS IN A MOLECULE TEND
TO REPEL OTHER LONE PAIRS AND OTHER
BONDING ELECTRON PAIRS.

4. ELECTRONEGATIVITY VALUES
OF ATOMS IN THE MOLECULE.
EN = DIFFERENCE IN
ELECTRONEGATIVITY.
AS EN INCREASES, BOND
POLARITY INCREASES.
ELECTRONS MOVE CLOSER TO
THE MORE ELECTRONEGATIVE
ATOM IN THE BOND.
COLUMN # AND BONDING TYPE
MOLECULAR SHAPE AND FORMULA
TELLS IF A POLAR
OR NONPOLAR
MOLECULE IS
FORMED
SHOWS MOLECULAR SHAPE
AND POLARITY OF BONDS
 MEANS PARTIALLY
+ OR – DUE TO ELECTRON
SHIFTS IN THE BOND
FRAME FORMAT

5. LINEAR - LiCl
ELECTRONS
TRANSFER TO
Cl FROM Li &
LiCl IS IONIC
COLUMN I - S BONDING
ELECTRONEGATIVITIES
Li = 1.0
Cl = 3.0
EN = 2.0
ELECTRONS TRANSFER
TO THE CHLORINE

6. 3D IONIC CRYSTAL LATTICE

7. LINEAR - BeCl2
-
+
-
POLAR BONDS
CANCEL & BeCl2
IS A NONPOLAR
MOLECULE
COLUMN II - SP BONDING
ELECTRONEGATIVITIES
Be = 1.5
Cl = 3.0
EN = 1.5
ELECTRONS SHIFT
TOWARD CHLORINE

8. TRIGONAL PLANAR - BCl3
(FLAT TRIANGLE)
-
+
ELECTRONEGATIVITIES
B= 2.0
Cl = 3.0
EN = 1.0
ELECTRONS SHIFT
TOWARD CHLORINE
-
-
POLAR BONDS
CANCEL & BCl3
IS A NONPOLAR
MOLECULE
COLUMN II - SP2 BONDING

9. TETRAHEDRAL - CCl4
-
+
ELECTRONEGATIVITIES
C = 2.5
Cl = 3.0
EN = 0.5
ELECTRONS SHIFT
TOWARD CHLORINE
-
-
-
POLAR BONDS
CANCEL & CCl4
IS A NONPOLAR
MOLECULE
COLUMN IV - SP3 BONDING

10. PYRAMIDAL – NH3
1 LONE e-
PAIR
-
+
+
+
ELECTRONEGATIVITIES
H = 2.1
N = 3.0
EN = 0.9
ELECTRONS SHIFT
TOWARD NITROGEN
POLAR BONDS
DO NOT CANCEL
& NH3 IS A POLAR
MOLECULE
COLUMN V - SP3 BONDING

11. 11
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