Physical Science - Quarter 1 - Lesson 3

1. LESSON 3
POLARITY OF
MOLECULES
SENIOR HIGH
SCHOOL PHYSICAL
SCIENCE

2. OOTD: OBJECTIVES OF THE DAY!
At the end of this lesson, you should be able to:
1. define electronegativity;
2. find the electronegativity of elements in the
periodic table;
3. distinguish between polar and non-polar
molecules;
4. relate the properties of molecules to its polarity
and its application and importance in our daily life.

3. INTRODUCTION
MOLECULE

4. INTRODUCTION
• Molecule is a group
of two or more
atoms held
together by
chemical bonds.

5. EXAMPLE OF MOLECULES
WATER SALT OZONE NITROGEN

6. EXAMPLE OF MOLECULES
ETHYL
ALCOHOL
ISOPROPYL
ALCOHOL
SUGAR COFFEE

8. HOWTO PLAY?
Read the group of unrelated words and
solve them into real words/phrases
before time runs out.

12. GUESSTHE GIBBERISH #1
LAW OWN PAY AIR

13. GUESSTHE GIBBERISH #2
PAW LIAR BANE END

14. GUESSTHE GIBBERISH #3
EEL LEAKTRUE NEED GOTTHIEVES
BEAT TEA

15. GUESSTHE GIBBERISH #4
NOON FOE LARD BOON AND

16. GUESSTHE GIBBERISH #5
MALL LET CURE LIAR
JAW MEETTHREE

17. LIST OF IMPORTANTTERMS
1. Lone Pair
2. Electronegativity
3. Polar Bond
4. Non-Polar Bond
5. Molecular Geometry

18. POLARITY
• It refers to the distribution of electric charge
around atoms, chemical groups, or molecules.

19. 2 FACTORSTHAT DETERMINE THE
POLARITY OF MOLECULES
1. The 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.

20. POLARITY OF MOLECULES
• All compounds can be classified based on what type of
chemical bond formed when the atoms combined.
• The classification of the compound can be used to
determine whether a molecule is polar or non-polar.
• The two classifications of compounds are covalent and
ionic.

21. COVALENT AND IONIC
• Covalent Compound is a molecule formed by covalent bonds,
in which the atoms share one or more pairs of valence
electrons.
• Ionic Compounds are made up of ions rather than molecules.
Instead of sharing electrons in covalent bonds, ionic
compound atoms transfer electrons from one atom to
another to form an ionic bond that relies on electrostatic
attraction to keep the atoms together.

22. BOND POLARITY
• ELECTRONEGATIVITY (EN)
• It is the measure of 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 electron toward itself.

24. ELECTRONEGATIVITY DIFFERENCE
DIFFERENCE IN
ELECTRONEGATIVITY
TYPE OF COMPOUND
(BOND POLARITY)
Greater than
or equal to 1.7
IONIC
O.5 – 1.6
COVALENT
POLAR
Less than 0.5 NON-POLAR

25. EXAMPLE
1. Predict whether the bond type between the following pairs of
atoms will be ionic, polar covalent, or nonpolar covalent.
1. C and Cl
2. Mg and O
3. H and Cl
4. N and N
5. K and F

26. MOLECULAR POLARITY
• For polyatomic molecules, both the bond
polarity and molecular shape determine the
overall molecular polarity.
H2O, CCl4, NH3 and CO2

27. MOLECULAR POLARITY
• 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 molecule.

28. SHAPES UNDERVSEPR THEORY