Chapter 6

Question 1

4: 0

Answer 1

tetrahedral

109.5

Question 2

3: 1

Answer 2

pyramidal

107

Question 3

2: 2

Answer 3

non-linear

104.5

Question 4

2 areas of electron density

Answer 4

linear

Question 5

3 areas of electron density

Answer 5

trigonal planar

Question 6

4 areas of electron density

Answer 6

tetrahedral

Question 7

5 areas of electron density

Answer 7

bi-pyramidal

Question 8

6 areas of electron density

Answer 8

octahedral

Question 9

what is electronegativity

Answer 9

the attraction of a bonded atom for the pair of electrons in a covalent bond

Question 10

What is a dipole

Answer 10

A separation of opposite charges within a molecule.

Question 11

Permanent dipole

Answer 11

This is a dipole in a covalent bond and it doesn’t change.

Question 12

Polar solvents and solubility

Answer 12

Since H2O is also a polar molecule, any polar solvents can also dissolve in it. The water molecules attract the ions and the lattice breaks down

Question 13

Covalent bonding

Answer 13

Strong and they hold atoms in a molecule together

Question 14

IMF

Answer 14

Weak interaction between dipoles of different molecules.

Question 15

London forces

Answer 15

They exist between all molecules, polar or non-polar. They act between induced dipoles.

Question 16

London forces depend on

Answer 16

The more the electrons in each molecule:
the larger the dipoles
the greater the London interaction
the stronger the attractive forces

Question 17

Permanent dipole-dipole interactions

Answer 17

They act between the permanent dipoles in different polar molecules.

Question 18

simple molecular substances and solubility

Answer 18

Simple molecular compound is added to a non-polar solvent, IMF form between the molecules and the solvent. The interactions weaken the IMF and they break down meaning it dissolves.

Question 19

Electrical conductivity

Answer 19

There are no mobile charged particles in simple molecular structures.
With no charged particles that can move, there is nothing to complete an electrical circuit.

Question 20

Where do hydrogen bonds occur

Answer 20

Between
H- O
H- F
H- N

Question 21

what is an ionic bond

Answer 21

Electrostatic attraction between oppositely charged ions.

Question 22

how are London forces created?

Answer 22

When 1 atom approaches another atom and the approaching atom’s electron shells repel the electrons of the other atoms’. This results in slightly exposing the nucleus of the other atom and it creates an electrostatic attraction between the electron shells of one atom and the exposed nucleus of the other atom. This creates a dipole, which then induces a dipole in the atom’s neighbouring atoms.
They are being broken and remade all the time.

Question 23

When is a molecule non-polar?

Answer 23

When the 2 atoms bonded are of the same element, so the difference in electronegativities is 0.

Question 24

When is a molecule non-polar (ex. answer)?

Answer 24

If all the dipoles in a molecule are symmetrical, then the dipoles in the molecules cancel each other out. Because the molecule has no net dipole, it is now non-polar.

Question 25

When is a molecule polar (ex. answer)?

Answer 25

If all the dipoles are not of equal magnitude and not directly opposing each other, it means the dipoles are asymmetrical. Hence, the dipoles can't cancel each other out, leaving the molecule with a net dipole and hence the molecule is polar.

Question 26

How does electronegativies change in the Periodic Table?

Answer 26

Decreases down the group. | Increases as you move across a period.

Question 27

Why does electronegativities decrease down a group?

Answer 27

Because as you go down a group, you increase the atom's radius, and you increase the amount of electron shielding. This reduced the attraction between the valence electron and nucleus.

Question 28

Why does electronegativity increase across a period?

Answer 28

Elements have the same number of shells, but they increase in number of protons in the nucleus. This increase the effective nuclear charge, and also increases the attraction between the nucleus and the valence electron.

Question 29

The larger the EN...

Answer 29

The larger the dipole.

Question 30

How are simple molecular lattices held together.

Answer 30

The atoms are held by strong covalent bonds, and then the molecules are held together by weaker IMF.

Question 31

Why do simple molecular lattices have small melting and boiling points?

Answer 31

Because it doesn't require much energy to break the weak intermolecular forces.

Question 32

What is the solubility of simple molecular lattices?

Answer 32

They have weak dipoles and tend to be soluble in non-polar solvents and insoluble in water.