Electronegativity and Bonds

Open Ended

What do you think will happen when salt is added to water and stirred?

Open Ended

What do you think will happen when sugar is added to water and stirred?

Open Ended

A penny is added to water and stirred.

Key Question and Objectives

Key Question

What makes a atoms stick together?

Objectives

•

describe the different types of bonding that
correspond to different combinations of
electronegative atoms

•

use the electronegativity scale to compare atoms and
to compare (calculate) the polarity of different bonds

•

predict the properties of a substance based on its
chemical formula and bonding type.

Discussion Notes (1 of 6)

Electronegativity:The tendency of an atom to attract the electrons that
are involved in bonding.
• This is on a 4 point scale, the higher the number the stronger the electronegativity.

Dropdown

Click on the picture to make it larger to help you complete this sentence



Based on the scale electronegativity values appear to ​

Select answer

as you move left to right across a period (row).

Dropdown

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As you go from the top to the bottom in a group (column) the electronegativity value ​

Select answer

.

Discussion Notes (2 of 6)

Dipole:A polar molecule or a polar bond between atoms. A crossed arrow is used to show the direction of a dipole. The crossed end of the arrow indicates the partial positive (+), less electronegative, end of the polar bond, and the arrow points in the direction of the partial
negative (–), more electronegative, end.

​δ means "partial"

Discussion Notes (2 of 6)

Based on the table of electronegativity values below the dipole arrow is with the cross over the less electronegative atom and pointed towards the more electronegative atom.

Draw

Based on the table of electronegativity values below the dipole arrow in the correct direction above the three example bonds.

Bonds that involve sharing or transferring electrons fall
into three categories.
1. Nonpolar Covalent

a. Differences in electronegativity values is

0.5 or Less.

2. Polar Covalent

a. Differences in electronegativity values is

Between 0.6 and 1.9

3. Ionic

a. Differences in electronegativity values is

1.9 or Greater

Discussion Notes (3 of 6)

Discussion Notes (2 of 6)

• Nonpolar Covalent Differences in electronegativity values is 0.5 or Less.

• Polar Covalent
  Differences in electronegativity values is between 0.6 and 1.9

• Ionic
  Differences in electronegativity values is 1.9 or Greater

For N-As: 3.04 - 2.18 = 0.86 so it would be Polar Covalent

For P-S: 2.58 - 2.19 = 0.39 so it would be Nonolar Covalent

For Rb-O: 3.44 - 0.82 = 2.62 so it would be Ionic

Discussion Notes (4 of 6)

Ionic bonding:A type of chemical
bonding that is the result of transfer
of electrons from one atom to
another.

Properties of ionic substances:
• Dissolve in water (usually)
• Conduct electricity when dissolved
in water

• Tend to be brittle solids
• Made of metal and nonmetal atoms combined

Sodium

chloride, NaCl

(Table Salt)

Calcium

carbonate, CaCO3
(Antacid tablets)

Explore the simulation on the next slide to see what happens with electrons in an ionic bond.

Modeling Ionic Bonding

• You will need to select a compounds and turn on the "Ionization & Ionic Bond" option to see it in action.

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Discussion Notes (5 of 6)

Molecular Covalent:A type of chemical
bonding that is the result of valence
electrons being shared between pairs
or groups of atoms.
•This creates small stable units, called
molecules, within the substance.

Properties of molecular covalent
substances:
•Some dissolve in water, some do not

•Do not conduct electricity

•Some are liquids or gases

•Made entirely of nonmetal atoms

Sucrose,
C12H22O11

(Table Sugar)

Acetylsalicylic
Acid, C9H8O4

(Aspirin)

​

Explore the simulation on the next slide to see what happens with electrons in a covalent bond.

Modeling Covalent Bonding

• You will need to select a compounds and drag the atoms together to see it in action.

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Rose Gold,
AuCuAg (An
alloy of metals)

Discussion Notes (6 of 6)

Metallic bond:A bond
between metal atoms in which
the valence electrons are free
to move throughout the
substance.

Properties of metallic
substances:
• Do not dissolve in water
• Conduct electricity
• Bendable, malleable solids
• Made entirely of metal

atoms

Aluminium, Al

(Aluminium

Foil)

Explore the simulation on the next slide to see what happens with electrons in a metallic bond.

Modeling Metallic Bonding

• You will need to click the "Hit the metal plate with a hammer" button to interact with the simulation.

Math Response

What’s the difference in electronegativity for a F-N bond?

Remember to do the larger value minus the smaller value

Type answer here

Correct Answer: 0.94

Deg^°

Rad

Math Response

What’s the difference in electronegativity for a S-O bond?

Remember to do the larger value minus the smaller value

Type answer here

Correct Answer: 0.86

Deg^°

Rad

Math Response

What’s the difference in electronegativity for a Br-Na bond?

Remember to do the larger value minus the smaller value

Type answer here

Correct Answer: 2.03

Deg^°

Rad

Math Response

What’s the difference in electronegativity for a H-H bond?

Remember to do the larger value minus the smaller value

Type answer here

Correct Answer: 0.00

Deg^°

Rad

Categorize

Options (6)

Organize these options into the right bond

Nonpolar Covalent Diff. Less than 0.5

Polar Covalent Diff. between 0.5 & 1.9

Ionic Diff. Greater than 1.9