Module 3- Polarity of Molecules

Question 1

Two factors that determine the polarity of molecules:

Answer 1

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.

Question 2

The geometrical shape of the molecule which can be predicted via the

Answer 2

valence shell electron pair repulsion (VSEPR) theory.

Question 3

The higher the value of electronegativity, the more it tends to

Answer 3

attract electrons toward itself

Question 4

A. Polarity of Bonds

Answer 4

Covalent Bond

Ionic Bond

Question 5

covalent bond and ionic bond are

Answer 5

chemical bond

Question 6

Covalent Bond

Answer 6

also called a molecular bond, is a chemical bond that involves the sharing of electron pairs between atoms.

Covalent bonds results from the sharing of electrons between atoms.

Covalent bonds existing between the atoms is different from the attractive force between molecules which are called intermolecular forces.

Covalent bond is generally stronger.

Question 7

Covalent Bond also called a

Answer 7

molecular bond

Question 8

involves the sharing of electron pairs between atoms.

Answer 8

Covalent Bond

Question 9

Covalent bonds results from the sharing of

Answer 9

electrons between atoms

Question 10

Covalent bonds existing between the atoms is different from the attractive force between molecules which are called

Answer 10

intermolecular forces.

Question 11

Covalent bond is generally

Answer 11

stronger.

Question 12

is the complete transfer of valence electron(s) between atoms.

Answer 12

Ionic Bond

Question 13

It is a type of chemical bond that generates

Answer 13

two oppositely charged ions

Question 14

the _____ loses electrons to become a positively charged cation

Answer 14

metal

Question 15

In ionic bonds, the metal _____ to become a positively charged cation

Answer 15

loses electrons

Question 16

In ionic bonds, the metal loses electrons to become a

Answer 16

positively charged cation

Question 17

_____ accepts those electrons to become a negatively charged anion.

Answer 17

nonmetal

Question 18

nonmetal _____ to become a negatively charged anion.

Answer 18

accepts those electrons

Question 19

nonmetal accepts those electrons to become a _____.

Answer 19

negatively charged anion

Question 20

B. Polarity of Molecules

Answer 20

Polar covalent bonds

Non-polar covalent bonds

Question 21

occur when electron pairs are unequally shared. The difference in electronegativity between atoms is significant.

Answer 21

Polar covalent bonds

Question 22

The separation of charges makes the bond

Answer 22

polar

Question 23

The separation of charges makes the bond polar. It creates an

Answer 23

electric dipole

Question 24

refers to “two poles,” meaning there is a positive and a negative pole within a molecule.

Answer 24

Dipole

Question 25

Elements with the higher EN value become the

Answer 25

partial negative pole

Question 26

lower EN value become the

Answer 26

partial positive pole

Question 27

occur when electron pairs are shared equally or the difference in electronegativity between atoms is less than 0.5.

Answer 27

Non-polar covalent bonds

Question 28

Non-polar covalent bonds occur when electron pairs are shared equally or the difference in electronegativity between atoms is less than

Answer 28

0.5

Question 29

Bonding electrons shared unequally between two atoms. Partial changes on atoms

Answer 29

Polar covalent bond

Question 30

Bonding electrons shared equally between two atoms. No charges on atoms.

Answer 30

Non-polar covalent bonds

Question 31

The three-dimensional arrangement of the atoms that constitute a molecule. It includes

Answer 31

• general shape of the molecule
• bond lengths
• bond angles
• torsional angles
• other geometrical parameters

Question 32

is a representation of the valence electrons of an atom that uses dots around the symbol of the element.

Answer 32

Lewis Electron Dot Structure

Question 33

The number of dots equals the number

Answer 33

of valence electrons in the atom.

Question 34

Steps in drawing the Lewis dot structure

Answer 34

-count all valence electron
-determine the central atom
-draw single bond
-put all the remaining valence electrons on atom as one lone pair
-Turn pairs into double or triple bond to give every atom an octet or duet

Question 35

A few general rules apply to determining the skeleton of the Lewis structure:

Answer 35

Carbon is usually a central atom. In compounds with more than one carbon atom, the carbon atoms are joined in a chain to start the skeleton.

Hydrogen is never a central atom because it can only form one covalent bond.

Halogens form only single covalent bond when oxygen is not present, therefore a halogen will generally not be a central atom.

Oxygen forms only two covalent bonds and is rarely a central atom, however it may link two carbon atoms in a carbon chain.

In the simpler molecules, the atom that appears only once in the formula will be the central atom.

Question 36

2nd step:

Answer 36

Count the number of BONDING PAIR and LONE PAIR on the central atom

Question 37

3rd step:

Answer 37

Decide on the electron pair orientation using the TOTAL NUMBER OF ELECTRON PAIR.