Molecular Polarity

Molecular Polarity

Synthesis Session

Poll

Self- Assessment:

• I can define what chemical bonding is and explain why it happens.

• CRYSTAL CLEAR

• CLEAR ENOUGH

• BLURRY

Poll

Self- Assessment:

• I can differentiate the different types of chemical bonds from one another.

• CRYSTAL CLEAR

• CLEAR ENOUGH

• BLURRY

Poll

Self- Assessment:

• I can identify the type of chemical bond present between two atoms.

• CRYSTAL CLEAR

• CLEAR ENOUGH

• BLURRY

Poll

Self- Assessment:

• I can determine verbally if a molecule is polar or non-polar given its structure.

• CRYSTAL CLEAR

• CLEAR ENOUGH

• BLURRY

Poll

Self- Assessment:

• I can relate the polarity of a molecule to its properties.

• CRYSTAL CLEAR

• CLEAR ENOUGH

• BLURRY

REVIEW of the

LESSON PLAYLIST RESPONSES and FEEDBACK

Open Ended

Synthesis Question 1:

What is a chemical bond?

Synthesis Question 1:

What is a chemical bond?

an electrical attraction between the nuclei and valence electrons of an atom and which binds atoms together.

Open Ended

Synthesis Question 2:

Differentiate the three (3) types of chemical bonds that may exist in substances: ionic, covalent, and metallic.

Types of Chemical Bonds

a. ionic – transfer of electrons

(metal and nonmetal )(cation and anion)

Types of Chemical Bonds

b. covalent – sharing of electrons (among nonmetals)

Types of Chemical Bonds

c. metallic – existing among metals

Open Ended

Synthesis Question 3:

How will you differentiate POLAR from NON-POLAR covalent bond?

Non-polar covalent bond

• electrons are equally shared by the bonded atoms.

• balanced distribution of electrical charge

• electrons spend the same length of time in the locality of each atom

Polar covalent bond

• bonded atoms have an unequal sharing of electrons (partial electron transfer) 

Multiple Choice

Concept Check 1:

In a polar covalent bond, the electron density (length of time of the electrons in the locality of each atom) is the same around the nuclei of the atoms involved.

• True

• False

Multiple Choice

Concept Check 2:

In a polar covalent bond, the electrons are closer to the more electronegative atom.

• True

• False

DIPOLE MOMENT



Dipole Moment

• the two partially charged regions or poles of a molecule are referred to as a dipole.

• symbolized by an arrowhead to the more electronegative atom (negative pole), and a crossed tail located at the less negative atom (positive pole)

Open Ended

Synthesis Question 4:

What is electronegativity?

Electronegativity

A measure of the tendency of an atom to attract electrons toward itself.

HOW TO DISTINGUISH A NONPOLAR FROM A POLAR COVALENT BOND?

Concept Check 3

Predict first if the bond between each pair of atoms is ionic or covalent. Further, classify the covalent bond as either polar or nonpolar using the concept of electronegativity. Determine the more electronegative atom in each pair.

For 5 minutes, answer the items above using your notebook and get ready with your answers in the next Quizizz Fill-in-the-blanks questions.

Multiple Choice

Pair 1: Chlorine and Potassium

TYPE of BOND

• Ionic

• Polar

• Non-polar

Multiple Choice

Pair 1: Chlorine and Potassium

MORE ELECTRONEGATIVE ATOM

• Chlorine

• Potassium

Multiple Choice

Pair 2: Chlorine and Carbon

TYPE of BOND

• Ionic

• Polar

• Non-polar

Multiple Choice

Pair 2: Chlorine and Carbon

MORE ELECTRONEGATIVE ATOM

• Chlorine

• Potassium

Multiple Choice

Pair 3: Two atoms of Chlorine

TYPE of BOND

• Ionic

• Polar

• Non-polar

Multiple Choice

Pair 3: Two atoms of Chlorine

MORE ELECTRONEGATIVE ATOM

• Cannot be determined

• Same

MOLECULAR GEOMETRY and POLARITY

• A molecule whose bonds are all nonpolar in character is likely to be nonpolar overall.

• However, NOT ALL POLAR COVALENT BONDS result to POLAR MOLECULES!!!

• Molecule polarity is also affected by the molecular geometry, which in turn is influenced by the electrons in the molecule.

MOLECULAR GEOMETRY and POLARITY

• The polarity of an atom-atom bond may be different from the polarity of the whole molecule itself. 

MOLECULAR GEOMETRY and POLARITY

•The difference in the electron density of each atom makes EACH Be-H bond POLAR.

• However, since the molecular geometry of BeH₂ is LINEAR and the two poles are on the OPPOSITE SIDES, the polarities “CANCEL OUT”, which makes the whole molecule NONPOLAR. (NO DIPOLE MOMENT!)

NOTES on MOLECULAR GEOMETRY and POLARITY

• When determining the polarity of a molecule, it is all about symmetry.

• Asymmetric molecules tend to be polar. 

• Symmetric molecules are always non-polar. 

COMMON MOLECULAR GEOMETRIES

Polar or non-polar?

Key

• 1. Nonpolar

• 2. Nonpolar

• 3. Nonpolar

• 4. Nonpolar

• 5. Nonpolar

Key

• 6. Polar

• 7. Polar

• 8. Polar

EXERCISES

Given the Lewis structure, predict if each substance is polar or non-polar.

Multiple Choice

1. N₂

• Polar

• Non-polar

Multiple Choice

2. SO₂

• Polar

• Non-polar

Multiple Choice

3. BrF₃

• Polar

• Non-polar

Multiple Choice

4. HCN

• Polar

• Non-polar

Multiple Choice

5. CH₂Cl₂

• Polar

• Non-polar

Open Ended

GIve at least two (2) insights you had from our discussions.