Chapter 6

Question 1

What is the shapes of and bond angles in a molecule with two bond pairs of electrons?

Answer 1

bond angle- 180

shape- linear

Question 2

What is the shapes of and bond angles in a molecule with three bond pairs of electrons?

Answer 2

bond angle- 120

shape- trigonal planar

Question 3

What is the shapes of and bond angles in a molecule with four bond pairs of electrons?

Answer 3

bond angle- 109.5

shape- tetrahedral

Question 4

What is the shapes of and bond angles in a molecule with six bond pairs of electrons?

Answer 4

bond angle- 90

shape- octahedral

Question 5

What is the shapes of and bond angles in a molecule with three bond pairs and 1 lone pair of electrons?

Answer 5

bond angle- 107

shape- pyramidal

Question 6

What is the shapes of and bond angles in a molecule with two bond pairs and 2 lone pairs of electrons?

Answer 6

bond angle- 104.5

shape- non-linear

Question 7

What do lone pairs do in shape of molecules?

Answer 7

Repel more strongly than bonded pairs, decreasing the bond pair by 2.5 per lone pair.

Question 8

What is electronegativity?

Answer 8

It is the ability of an atom to attract the bonding electrons in a covalent bond.

Question 9

How is electronegativity affect the periodic table?

Answer 9

It increase across a period and decreases down the groups. Elements in the top right hand corner are the most electronegativity.

Question 10

What is a polar covalent bond?

Answer 10

When the bonding electrons between two atoms with differing electronegativity are shared unequally.

Question 11

What happens to the dipoles in symmetrical molecules?

Answer 11

The dipoles cancel out so there are no permanent dipoles.

Question 12

What happens to the dipoles in unsymmetrical molecules?

Answer 12

The dipoles do not cancel each other out so the molecules has permanent dipoles and is polar.

Question 13

What are the temporary dipoles?

Answer 13

The distribution of electrons in an atom or non-polar molecule is random, so temporary dipoles will exist - these are constantly shifting.

Question 14

What are London forces?

Answer 14

London forces exist between all molecules and are the attraction between temporary dipoles and the induced-dipoles by cause in neighbouring species.

Question 15

What are permanent dipole-dipole interactions?

Answer 15

Permanent dipole-dipole interactions are stronger and exist between molecules with permanent dipoles where electron distribution is less random.

Question 16

What is hydrogen bonding?

Answer 16

Is the intermolecular bonding between molecules containing N, O or F with a lone pair, and the H atoms f -NH, -OH or -HF.

Question 17

What is the strongest type of intermolecular force?

Answer 17

Hydrogen bonding

Question 18

Why does ice float?

Answer 18

Ice is less dense than liquid as the H2O molecules are held further apart in the solid crystal structure by the arrangement of the hydrogen bond.

Question 19

Why does water have a high surface tension?

Answer 19

Because of the molecules on the surface experiencing unbalanced hydrogen bonding forces pulling them in.

Question 20

What is a simple molecular lattice?

Answer 20

Is the soild structure of covalently bonded molecules attracted together by intramolecular forces.