Unit A - Bonding

Question 1

What are valence electrons?

Answer 1

Electrons in the highest energy level around the nucleus. They are found in the outermost energy level of an atom.

Question 2

What is Electronegativity?

Answer 2

The tendency for an atom to attract valence electrons.

Electronegativity gradually increases as we move from the left to right in a period.

Electronegativity decreases as we move down the group.

Question 3

What are the trends in the periodic table?

Answer 3

If it goes right electronegativity increases due to electrons in the valence getting more and more desperate to fill the orbitals.

If it goes down electronegativity decreases because the actual size of the molecules increases.

Right: Electronegativity increases - electrons in valence having more desperation to fill orbitals.

Down: Electronegativity decreases - actual size of molecules increases.

Question 4

Which electrons determine the molecule’s shape?

Answer 4

Valence electrons

Question 5

What is AXE and what does each letter represent?

Answer 5

A - # of molecules around the central molecule.
X - # of bonding pairs.
E - # of lone pairs.

Question 6

What are the names of the possible 5 molecular shapes?

Answer 6

• Linear
• Trigonal Planar
• Tetrahedral
• Trigonal Pyramid
• Bent

Question 7

What are the general AXE formulas?

Answer 7

AX2, AX3, AX4, AX3E, AX2E2

Question 8

How do we know which end of the molecule is slightly positive?

Answer 8

We can know which end of the molecule is slightly positive by the plus sign.

Question 9

Slightly negative?

Answer 9

It is when the atom that attracts the electrons more will get a slightly negative charge since electrons will spend more time around that atom.

Question 10

What is a bond dipole?

Answer 10

Charge separation which occurs as a result of the different electronegativities of the bonded atoms.

Question 11

What is so special about the number 1.7 when it comes to chemical bonding?

Answer 11

The thing that is special about the number 1.7 is that when the difference in electronegativity is greater than 1.7 then it will be ionic. When the difference in electronegativity is between 0.5 and 1.7 it is a polar covalent bond.

Question 12

What are intramolecular forces?

Answer 12

Forces that keep the atoms within a compound “stuck” together.

Question 13

Are they stronger than all of the intermolecular forces?

Answer 13

They are stronger than all of the intermolecular forces.

Question 14

What are intermolecular forces?

Answer 14

Forces that are accountable for keeping the molecules together in solid, liquid, or gaseous form.

Question 15

What are the 3 types?

Answer 15

London dispersion forces, Dipole-dipole forces, Hydrogen bonding

Question 16

Can you rank them in order of strongest to weakest?

Answer 16

Hydrogen bonding, dipole-dipole forces, London dispersion forces

Question 17

What determines the strength of the London forces?

Answer 17

The thing that determines the strength of the London forces is the greater the number of electrons in the atoms of a molecule the greater the London dispersion forces.

Question 18

What is hydrogen bonding and what atoms does it occur between?

Answer 18

It is when it is directly bonded to a highly electronegative atom.

The atoms that it occurs between are nitrogen, oxygen or fluorine.

Question 19

Can you use intermolecular forces to explain trends in melting points and boiling points?

Answer 19

I think we can use intermolecular forces to explain trends in melting points and boiling points. During high boiling point stronger forces are acting which means they are intermolecular forces because they are stronger than intramolecular molecules.

Question 20

Why are metals malleable?

Answer 20

Metals are malleable because bonds are between cations and a sea of electrons rather than between cations and cations; cations may be moved in the sea of electrons without breaking bonds.

Question 21

What is the metallic bonding model?

Answer 21

Metallic bonding model is an array of cations in a sea of valence electrons.

Question 22

Can you explain conductivity of solid ionic, aqueous ionic, and molecular compounds?

Answer 22

During the solid ionic, both the positively and negatively charged ions stay in place. There will be no current on a conductivity testing meter during the solid ionic.

During the aqueous ionic, it will conduct electric current since the ions are free to move toward the oppositely charged molecule.

During the molecular compounds, charges cannot leave the molecule and no electric current will flow.

Question 23

What is a Covalent Bond?

Answer 23

It is created when both electronegativities are high.

Question 24

What is a Ionic Bond?

Answer 24

It is created when the difference in electronegativities are quite large.