3.1.3 Bonding

Question 1

Ionic bonding

Answer 1

Involves electrostatic attraction between oppositely charged ions in a lattice

Question 2

Sulfate ion

Answer 2

SO₄²-

Question 3

Hydroxide ion

Answer 3

OH¯

Question 4

Nitrate ion

Answer 4

NO₃⁻

Question 5

Carbonate ion

Answer 5

CO₃²⁻

Question 6

Ammonium ion

Answer 6

NH₄+

Question 7

Metallic bonding

Answer 7

Involves attraction between delocalised electrons and positive ions arranged in a lattice.

Question 8

4 types of crystal structure + examples

Answer 8

Ionic - NaCl
Metallic - Mg
Macromolecular (giant covalent) - Diamond/Graphite
Molecular - Iodine/Water

Question 9

Ionic melting point

Answer 9

High as the electrostatic forces of attraction between the positive and negative ion requires a lot of energy to be overcome

Question 10

Ionic conductivity

Answer 10

Only when molten or in solution as they are free to move and carry a flow of charge

Question 11

Are ionic compounds brittle

Answer 11

Yes as when the layers of alternating charges are distorted, like charges repel, breaking the compound

Question 12

Metal boiling point

Answer 12

Very high, as bond between positive metal ion and delocalised electrons is very taring and requires a lot of energy to overcome

Question 13

Metals as conductors

Answer 13

Yes as sea of delocalised electrons is free to carry charge

Question 14

Are metals brittle or malleable

Answer 14

Malleable as layers of positive ions are able to slide over each other. sea of delocalised electrons prevent fragmentation as they can move around the lattice

Question 15

Simple molecular bonding

Answer 15

Covalently bonded molecules
Held together with weak VDWs
Low boiling point as VDWs easy to break
(exception water as it has hydrogen bonding)

Question 16

Macromolecular

Answer 16

Many covalent bonds
Very high melting point as lots of energy is required to break covalent bonds
Rigid

Question 17

Graphite structure

Answer 17

Each carbon is bonded to 3 others in a sheet
One electron per carbon is free to move around
So can conduct electricity
Sheets of carbon can move over each other easily

Question 18

Electron repulsion (most to least)

Answer 18

Lone pair - Lone pair
Lone pair - Bonding pair
Bonding Pair - Bonding pair

Question 19

Linear

Answer 19

Bonding pairs: 2
Lone pairs: (3)
Bond angle: 180 (120)

Question 20

V-shaped

Answer 20

Bonding pairs: 2
Lone pairs: 2
Bond angle: 104.5

Question 21

Trigonal planar

Answer 21

Bonding pairs: 3
Lone pairs: 0
Bond angle: 120

Question 22

Triangular Pyramidal

Answer 22

Bonding pairs: 3
Lone pairs: 1
Bond angle: 107

Question 23

Tetrahedral

Answer 23

Bonding pairs: 4
Lone pairs: 109.5
Bond angle:

Question 24

Trigonal bipyramidal

Answer 24

Bonding pairs: 5
Lone pairs: 0
Bond angle: 90 &120

Question 25

Octahedral

Answer 25

Bonding pairs: 6 Lone pairs: 0 Bond angle: 90

Question 26

Electronegativity

Answer 26

The power of an atom to attract the pair of electrons in a covalent bond. Increases a long a period, decreases down the group.

Question 27

Permanent dipole

Answer 27

when the two bonded atoms have a large enough difference in electronegativity, the more electronegative atom draws more of the negative charge towards itself. This is a polar molecule. Symmetrical molecules are not polar.

Question 28

How do induced dipoles arise

Answer 28

Electrons move randomly through the atom, so at any point there may be more on one side than other This temporary dipole can induce an opposite dipole in a neighbouring atom This induced dipole can then induce further dipoles in other nearby particles. Overall effect is net attraction between molecules

Question 29

Van der Waals

Answer 29

Weak IMF acting as an induced dipole between molecules. The more points of contact, the more VDWs so the higher the melting point. So branched chains usually have lower boiling points as they can line up/pack as closely.

Question 30

Hydrogen bond

Answer 30

Strongest IMF, acts between hydrogen and either N, O or F. The lone pair on these atoms forms a H bond with the Hydrogen, shown by a dotted line. these molecules have higher b.ps. R - O: - - - - - - H