Its sexayyy.

1. Shapes of Covalent Molecules
By Chris Johnston

2. Regular Covalent Molecules
C OO C
H
H
H
H

3. Figuring out the Shape of a Regular
Covalent Molecule
1. In the Bond, pick out the ‘main’ atom and work
out how many electrons it has in the outer energy
level.
Cl4C
1 12 23 34 4

4. Figuring out the Shape of a Regular
Covalent Molecule
2. Draw out a completed dot and cross diagram of
the molecule to make sure there are no lone pairs
of electrons. Also count the number of bonded pairs.
Cl
Cl
Cl
Cl
Lone Pairs:
Bonded Pairs:
0
01234

5. Figuring out the Shape of a Regular
Covalent Molecule
3. Using the number of bonded pairs, find out
the shape of the regular molecule.
No. of
Bonded Pairs
Name of
Shape
3D Shape 2D Shape
+ Example
Bond Angles.
2 Linear
C OO
CO2
180°3 Trigonal
Planar
B
F
F
F
BF3
120°4 Tetra-
hedral
C
H
H
H
H
CH4
109.5°5 Trigonal
Bipyramidal
P
Cl
Cl
Cl
Cl
Cl
PCl5
90°
+
120°
6 Octahedral
S
F
F
F
F
F
F
SF6
90°

6. CCl4
Cl
Cl
Cl
ClC
Cl
Cl
Cl
Cl
109.5°

7. Irregular Covalent Molecules
N
H
H
H
O
H H

8. Figuring out the Shape of an Irregular
Covalent Molecule
1. In the Bond, pick out the ‘main’ atom and work
out how many electrons it has in the outer energy
level.
Cl3P
1 12 2334 45 5

9. Figuring out the Shape of an Irregular
Covalent Molecule
2. Draw out a completed dot and cross diagram of
the molecule and count the number of bonded and
lone pairs of electrons.
P
Cl
Cl Cl Lone Pairs:
Bonded Pairs:
0
0123
1

10. Figuring out the Shape of an Irregular
Covalent Molecule
3. Use the total number of pairs to figure out what
shape it is based on, then place the lone pair of
electrons.
Total Pairs = Bonded Pairs + Lone Pairs
Total Pairs = 3 + 1
Total Pairs = 4
P
Cl
Cl
Cl

11. Figuring out the Shape of an Irregular
Covalent Molecule
4. Use the angle of the regular shape, and the
number of lone pairs, to figure out the new bond
angle.
X
X X
Strength of Repulsion
Bonding Angle = Angle of Regular Shape - (Number of lone pairs x 2.5)
P
Cl
Cl
Cl
109.5° - 2.5° = 107°

12. Covalent Ions
O H[ ]-
N
HH[ ]
-

13. Figuring out the Shape of a Covalent
Ion
1. In the bond, pick out the ‘main’ atom and work
out how many electrons it has in its outer energy
level. Keep the charge in mind!
H3O+

14. Figuring out the Shape of a Covalent
Ion
2. Draw out a completed dot and cross diagram of
the molecule and count the number of bonded and
lone pairs of electrons.
Lone Pairs:
Bonded Pairs:
0
0123
1

15. Figuring out the Shape of a Covalent
Ion
3. Use the total number of pairs to figure out what
shape it is based on, then place the lone pair of
electrons.
Total Pairs = Bonded Pairs + Lone Pairs
Total Pairs = 3 + 1
Total Pairs = 4
O+
H
H
H

16. Figuring out the Shape of a Covalent
Ion
4. Use the angle of the regular shape, and the
number of lone pairs, to figure out the new bond
angle.
Bonding Angle = Angle of Regular Shape - (Number of lone pairs x 2.5)
O+
H
H
H
Bond Angle = 109.5° - 2.5 °
Bond Angle = 107 °