The Polarity of the Molecules

1. Molecular Polarity

2. The bond polarity is a result of combining atoms of
element having different electronegativity values.
The covalent bond is formed when two identical
atoms evenly shared their electrons.
Classified into 2:
a. Non-polar covalent bond
b. Polar covalent bond

3. Non-Polar Covalent Bond
When two atoms having similar electronegativity will share
electrons equally.
Polar Covalent Bond
When two bonded atoms are not equally distributed the
electrons, one atom is more electronegative than the other
atom, this bond is polarized, meaning one atom is partially
positive and the other atom is partially negative.

5. What is the game being shown in the pictures? Have
you tried playing this game with your friends or
classmates? Can you describe each team? Who is the
team going to win?

6. In picture A, the two princesses are pulling the prince toward to
them. It shows that the prince is equally shared to the princess.
In covalent bond, it would be classified as non- polar since the
bonding are evenly shared.
In picture B, it clearly shows that unbalanced number of persons
in each side. Let us say that the 2 persons is hydrogen (H) and
the 7 persons is fluorine (F), the electrons of two bonded atoms
will not share equally. This bond is called polar. In this case it will
form HF, fluorine is more electronegative than H. F attracts
bonding electron pair closer to itself then it will become
polarized. As a result, F end is partially negative and the atom of
hydrogen becomes partially positive

7. Molecular Polarity
The two bonding atoms with different
electronegativity values will result to have a bond
polarity. When molecules become more complex
will result to have a molecular polarity.
Refers to the total of the bond polarity of
bonded molecules.

8. First, we must determine if a molecule is a polar or non-
polar. A non-polar molecule is symmetric. If a molecule is
symmetric meaning. For instance, methane all electrons
are equally shared or bonded has a chemical formula of
(CH₄). It is a tetrahedral molecule and an example of non-
polar bond.

9. The polar molecule is asymmetric, meaning the
distribution of electrons in a covalent bond is not equal.
It also contains lone pairs of electrons on the central
atom or atom is bonded with different electronegativity
values. Polarity is a result of uneven distribution of
charges of atoms in a molecule. Covalent bond produces
partial charges either partial positive (δ+) and partial
negative (δ–) among atoms is called polar covalent bond.

10. An arrow ( ) indicates direction of shared electrons are
pulled.
Example:
ammonia (NH3 ) is a polar bond and has a molecular shape
of trigonal pyramidal.

11. Hydrobromic acid (HBr) is a polar, since bromine (Br) has
electronegativity value of 2.8 while hydrogen has 2.1
electronegativity value. Hence, Br is more electronegative
than H. Therefore, the arrow is directed to Br.
The diatomic molecules such as Br2 , O₂ , N2 , and H2 are all
non-polar. No atoms are more electronegative than the
other, the bonding electrons are evenly distributed.

12. The polar bond and non-polar bond can also be
determine through electronegativity difference
between molecules. The electronegativity
difference can be calculated by getting the
electronegativity value of the given molecules in
the periodic table of elements.

14. Activity

16. Valence Shell Electron Pair Repulsion (VSEPR)
theory
 Is a guide to predict the arrangement of atoms in a
polyatomic molecule.
 In determining the geometry of a molecule, you need to
identify first the central atom.
 Usually, the least numerous element, the least
electronegative element, or the element which can form
the most bonds is the central atom.
 Hydrogen can never be the central atom (except in H2 ) as
it can only form one bond.

17. In the water (H₂O ) molecule, the central atom is
oxygen since it is the least numerous element and can
form more bonds than hydrogen.
1. Create the appropriate Lewis dot structure of the
molecule.

19. Given the Lewis dot structure of H₂O above, we can then use
the following table to determine its molecular geometry.

21. We can now see that the molecular geometry shape of
water molecule is angular or bent. Moreover, looking at
the overall polarity of the water molecule we can
therefore say that water is a polar molecule, since it has
polar covalent bonds between H and O, and it has an
asymmetrical molecular geometry shape that is
angular/bent.

22. Polar molecules:

23. Non-Polar molecules:

24. Reference:
 file:///D:/DepEd%20(Sub)/Physical%20Science/Polar%20
or%20nonpolar.pdf