Chapter 3 - Bonding

Question 1

What are the four types of bonding?

Answer 1

Covalent molecules, covalent macromolecular lattices, metallic bonding, ionic bonding

Question 2

What is ionic bonding?

Answer 2

Ionic bonding is the attractive forces between oppositely charged ions in a lattice

Question 3

What molecular ions do you need to know and what is their charge?

Answer 3

Sulfate - SO4 (2-)
Nitrate - NO3 (-)
Carbonate - CO3 (2-)
Hydroxide - OH (-)
Ammonium - NH4 (+)

Question 4

What is a covalent bond?

Answer 4

A covalent bond is any shared pair of electrons between 2 atoms

Question 5

What is a dative, or coordinate, bond?

Answer 5

It is a type of covalent bond where both of the electrons have been supplied by one atom

Question 6

What is metallic bonding?

Answer 6

Metallic bonding is the type of bonding present in metals, where they delocalise all electrons in the outer shell into a “delocalised sea of electrons” becoming a positive ion which therefore experiences an attractive force between the nucleus and sea of electrons, arranging the ions in a lattice

Question 7

What features do metallic lattices have?

Answer 7

Conductive, ductile, malleable, high melting point

Question 8

What features do ionic lattices have?

Answer 8

Conductive when dissolved, soluble, high melting point

Question 9

What features do molecules have?

Answer 9

Brittle, low melting points, not conductive

Question 10

What is the order of repulsion strength from greatest to weakest around an atom, in terms of pairs of electrons in covalent molecules?

Answer 10

Lone pair - lone pair -> lone pair - bonding pair -> bonded pair - bonded pair

Question 11

What shaped molecule is Beryllium chloride?

Answer 11

BeCl2 - linear (2 pairs) - 180 degree bond angle

Question 12

What shaped molecule is methane?

Answer 12

CH4 - tetrahedral (4 pairs) - 109.5 degree bond angle

Question 13

what shaped molecule is boron trifluoride?

Answer 13

BF3 - Trigonal planar (3 pairs) - 120 degree bond angle

Question 14

What shaped molecule is potassium pentachloride?

Answer 14

PCl5 - Trigonal bipyramidal (5 pairs) - 90 degree and 120 degree bond angles

Question 15

What shaped molecule is sulfur hexafluroride?

Answer 15

SF6 - Octahedral (6 pairs) - 90 degree bond angle

Question 16

What shaped molecule is ammonia?

Answer 16

NH3 - Triangular pyramid (4 pairs - 1 of which is a lone pair) - 107 degree bond angle

Question 17

What shaped molecule is water?

Answer 17

H20 - V shaped (4 pairs - 2 of which are line pairs) - 104.5 degree bond angle

Question 18

What shaped molecule is chloride tetrafluroride?

Answer 18

ClF4- - Square planar (6 pairs - 2 of which are lone) - 85 degree bond angle

Question 19

What is the defintion of electronegativity?

Answer 19

Electronegativity is the ability of an atom to pull the electrons in a bond towards its nucleus

Question 20

Why does electronegativity increase?

Answer 20

The smaller an atom is and the larger nuclear charge it has the higher the electronegativity. Smaller atoms have less distance between the nucleus and the bonded electrons, so a stronger attractive effect and higher nuclear charge also increases pull effect

Question 21

Which atoms have the highest electronegativity?

Answer 21

Fluorine, nitrogen and oxygen have the highest electronegativity, the top right is the most electronegative of the periodic table and the bottom left is the least electronegative

Question 22

What does a large difference in electronegativity cause?

Answer 22

Polar molecules to form, due to the difference in electronegativity the electrons will be much closer to one atom than another, inducing a partial charge on both atoms leading to polarity

Question 23

What forces between molecules can form?

Answer 23

Hydrogen bonds ->
Permanent dipole - permanent dipole ->
Induced dipole - dipole (more often called Van der Waals forces)

Question 24

Why do VdWs form?

Answer 24

Electrons are constantly moving around in their orbitals around atoms, therefore there is a chance that at any given point in time the majority of the electrons will be more towards one side of the atom, creating an asymmetrical distribution of electrons which can cause a repulsive effect on other atoms electrons, creating charge differentials allowing very weak, temporary forces to form

Question 25

What allows VdWs to form more strongly?

Answer 25

More electrons present allows more points for VdWs to form