2. 1) Predict the results of the mixture.
2) Define electronegativity
3) Find the electronegativity of elements in the
periodic table.
4) Explain the VSEPR theory
5) Draw the geometry of molecules using the
VSEPR theory
3. Important terms that learners will encounter
a.Electronegativity
b.Covalent bond
c.Valence electron
d. Miscible
e. Dipole
f.Immiscible
5. Polarity Experiment
Procedure
1. Mix the following samples
well with a spoon and observe
their reactions
2. Stir the mixture.
3. Remember to wash and dry
the stirring rod after each use.
Group I: Water + vinegar
Group II: Water + oil Group
III: Water + gasoline Group
IV: Oil + vinegar Group V:
Oil + gasoline
Group VI: Honey +
gasoline
6. Mixture Mixed (/) Not Mixed (X)
Water + vinegar
Water + oil Water
+ gasoline Oil +
vinegar Oil +
gasoline
Honey + gasoline
7. Find it!
boiling points
melting points
oxidation number
Atomic number
Atomic weight/ atomic mass
Electronegativity
8. Two factors that determine the polarity of
molecules.
1.polarity of the bonds between atoms which
can be studied based on electronegativity
2.the geometrical shape of the molecule which
can be predicted via the valence shell electron
pair repulsion (VSEPR) theory
9. Electronegativity (EN)
- measure of the relative tendency of an atom to
attract electrons to itself when chemically combined
with another atom.
-the higher the value of electronegativity, the more
it tends to attract electrons toward itself.
10. Covalent bond
- is a chemical link between
two atoms or ions where the
electron pairs are shared
between them
11. 2 Types of Covalent bond
1. Polar Covalent Bond
2. Non- polar Covalent Bond
12. Polar covalent bonds
Polar covalent bonds occur when
electron pairs are unequally
shared. The difference in
electronegativity between atoms is
significant
13. Examples of compounds having
polar covalent bonds
HCl
EN of H = 2.1 EN of Cl = 3.0 ΔEN = 0.9
14. Examples of compounds having
polar covalent bonds
HF
EN of H = 2.1 EN of F = 4.0 ΔEN = 1.9
15. The separation of charges makes the bond
polar. It creates an electric dipole. Dipole
refers to “two poles,” meaning there is a
positive and a negative pole within a
molecule.
16. Elements with the higher EN value
become the partial negative pole while
elements with the lower EN value become
the partial positive pole. This makes the
molecule a polar molecule.
17. Non-polar covalent bonds
-occur when electron pairs are
shared equally or the difference in
electronegativity between atoms is
less than 0.5.
18. 1. H2
EN of H = 2.1 ΔEN = 0.0 NON-
POLAR MOLECULE; not a dipole
19. 2. Cl2
EN of Cl = 3.0 ΔEN = 0.0 NON-POLAR MOLECULE; not a dipole
3. F2
EN of F = 4.0 ΔEN = 0.0 NON-POLAR MOLECULE; not a dipole
23. Answer key
EN of C = 2.5
EN of F = 4.0
EN of Br = 2.8
ΔEN = 0.4 Non polar covalent bond
ΔEN = 1.5 Polar covalent bond
ΔEN = 0.7 Polar covalent bond
1. CH4
2. CF4
3.HBr
4. O2
EN of H = 2.1
EN of C = 2.5
EN of H= 2.1
EN of O = 3.4 ΔEN = 0.0 Non polar covalent bond
24.
25.
26. 4. HI
EN of H = 2.1 EN of I = 2.5 ΔEN = 0.4
POLAR MOLECULE; a dipole
27. Valence Shell Electron Pair Repulsion
theory or VSEPR theory
- helps predict the spatial arrangement
of atoms in a polyatomic molecule. The
shapes are designed to minimize the
repulsion within a molecule.
28. Guidelines to determine the VSEPR
shape of a molecule
1.Determine the central atom of a
molecule. The central atom is the least
electronegative element.
2.Count how many valence electrons the
central atom has.
29. 3.Count how many valence electrons
the side atoms have.
4.Create the appropriate Lewis
structure of the molecule.
30. 5.Using the Lewis structure as a guide,
determine the appropriate VSEPR shape
for the molecule.
6.Note how many electrons are shared and
unshared. This will help determine the
appropriate VSEPR shape.
