This is all about polarity of molecules

1. PHYSICAL SCIENCES

2. TELL WHETHER THE COMPOUND BELOW IS AN IONIC COMPOUND
OR A COVALENT COMPOUND BASED ON THE TYPE OF CHEMICAL
BOND PRESENT.
1. NaCl
2. CO2
3. CaCl2
4. CCl4
5. Fe2O3
6. N2O
7. PCl5
8. KBr
9. HCl
10. AlCl3

3. Why is
water
considered
polar?

4. ELECTRONEGATIVITY ( EN)
 a measure of an atom’s attraction
for the electrons it shares in a
chemical bond with another atom.
the ability of an atom to attract
electrons to itself.

5. FIGURE 1

6. Source: CO_Q1_Physical Science SHS
Module 3

7. ACTIVITY 1
SAMPLE ACTIVE
COMPOUND
ELECTRONEGATI
ITY DIFFERENCE
POLAR OR
NONPOLAR
TAP WATER 𝐻2𝑂
(dihydrogen oxide)
H-O =
VINEGAR 𝐶2𝐻4𝑂2
(acetic acid)
C-H = C-O =
C-C = O-H =
COOKING OIL 𝐶6𝐻8𝑂6
(triglyceride)
C-H = C-O =
C-C =
RUBBING ALCOHOL
𝐶2𝐻6𝑂
(ethanol)
C-H = C-O =
C-C =

8. ACTIVITY 2- POLARITY EXPERIMENT
Materials
 Water
 Vinegar
 Oil
 Alcohol
 6 disposable glasses
 Disposable Spoon

9. PROCEDURE
Obtain 6 clean disposable glasses and prepare the
following set-up.
Set-up 1: 1 cup water + 5 tablespoons vinegar
Set-up 2: 1 cup water + 5 tablespoons oil
Set-up 3: 1 cup water + 5 tablespoons alcohol
Set-up 4: 1 cup vinegar + 5 tablespoons oil
Set-up 5: 1 cup vinegar + 5 tablespoons alcohol
Set-up 6: 5 tablespoon oil + 5 tablespoons alcohol

10. 2. THOROUGHLY STIR EACH MIXTURE AND OBSERVE CAREFULLY.
Combination Observation Inference
Water + Vinegar
Water + Oil
Water + Alcohol
Vinegar + Alcohol
Vinegar+ Oil
Oil + Alcohol
Guide Questions:
a. Which of the following set-ups mixed well? Which did not?
b. What can you infer from the result of this activity?

11. REMEMBER!
 What is Electronegativity?
 Which attracts valence electrons better, more
electronegative or less electronegative atom?
 In the Lewis structure, to which atom dots ( valence
electrons) are drawn closer, more electronegative or less
electronegative?
 Will polar sample mix with nonpolar sample? Why?
 Will polar sample mix with another polar sample? Why?

12. THE IMPORTANCE OF POLARITY OF WATER ON LIFE ON
EARTH.
 Water’s polarity allows it to dissolve other polar
substances very easily.
 Because of their polarity, water molecules are
strongly attracted to one another, which gives
water a high surface tension.
 the only natural substance that can exist in all
three states of matter – solid, liquid, and gas –
at the temperatures normally found on Earth.
 Water has a high specific heat. water can
absorb a lot of heat without changing
temperature. It’s why swimming feels so
refreshing on a hot day.

13. MULTIPLE CHOICE- CHOOSE THE LETTER ONLY.
1. Which of the following molecules DO NOT have polar covalent
bonds?
a. NH3 b. CS2 c. BCl3 d. HBr
2. Which of the following bonds is the MOST polar?
a. H-Cl b. C-Cl c. H-H d. N-F
3. Which of the following pairs of atoms would form a nonpolar
covalent bond?
a. P-N b. C-S c. Ca-O d. Na-Cl

14. 4. Which of the following statements is INCORRECT?
a. Polar covalent bonds can be present in a nonpolar
molecule.
b. Polar bond forms when electrons are unequally
shared by two atoms in a compound.
c. Polar covalent bond is present if the
electronegativity difference between atoms is equal
or less than 0.4.

15. 5. What do you call the relative ability of a bonded atom to attract shared
electron pairs?
A. Electron affinity b. Electronegativity c. Ionization energy d. Metallic
property
True or False: Write TRUE if the statement is correct, otherwise write FALSE
6. S and O are bonded by a polar covalent bond because its electronegativity
difference value is 1.0.
7. Atoms with high electronegativity have a greater tendency to attract electrons
toward itself.
8. Among C-Cl, H-Cl, C-H and Cl-Cl, only Cl-Cl is polar.
9.Methyl alcohol, CH3OH, is a nonpolar molecule.

16. Essay: 5 points
 1. Give two reasons why the
polarity of water is essential to life
on Earth.

17. ASSIGNMENT
Research in advance the different molecular
shapes

19. POLARITY OF MOLECULES AND MOLECULAR GEOMETRY
How will you predict the
type of bond polarity
present in a certain atoms?
specifically two atoms?

20. THE TWO WAYS IN PREDICTING THE TYPE OF BOND
POLARITY
 1. electronegativity difference
2. In terms of molecular geometry, the valence
shell electron pair repulsion (VSEPR) theory
would help us to determine the spatial
arrangement of atoms in a polyatomic

21. VALENCE SHELL ELECTRON PAIR REPULSION ( VSEPR)
THEORY
Covalent molecules assume geometry
that minimizes repulsion among
electrons in valence shell of atom
Shape of a molecule can be predicted
from its Lewis Structure

22. The valence shell electron pair repulsion
(VSEPR) theory is a model used to predict 3-D
molecular geometry based on the number of
valence shell electron bond pairs among the
atoms in a molecule or ion. This model
assumes that electron pairs will arrange
themselves to minimize repulsion effects from
one another.
VALENCE SHELL ELECTRON PAIR REPULSION ( VSEPR)
THEORY

23. YOU CAN PREDICT THE SHAPE OR MOLECULAR GEOMETRY OF A
SUBSTANCE USING THE FOLLOWING STEPS:
 Step 1: Determine the central atom of a molecule. The central
atom is the least electronegative element.
 Step 2: Draw the appropriate Lewis dot structure for the
molecule.
 Step 3: Count the number of bonding pairs of electrons and
non-bonding (or lone pairs) around the central atom. Step 4:
Determine the electron pair orientation using the total number
of electron pairs.
 Step 5: Name the shape based on the location of the atoms

26. CONSIDER THE EXAMPLE:

27. CO2
1. Compute the EN
2. Determine the central atom and terminal
atom.
3. Draw the Lewis structure
4. Identify the molecular geometry
5. Determine the bond polarity