AS periodicity + structure

Question 1

How is the periodic table arranged?

Answer 1

In atomic numbers , groups and periods

Question 2

3 factors affecting ionisation energies

Answer 2

1. Nuclear charge - ↑ proton = ↑ attraction
2. Atomic radius - ↑ dist. = ↓ attraction
3. Shielding - ↑ shells = ↑ repulsion

Question 3

What stays relatively constant throughout the period

Answer 3

Atomic radius and shielding

Question 4

3 exceptions to the steady ↑ in
ionisation energy across period

Answer 4

1. group 2 -> 3
2. group 5 -> 6
3. increase in period

Question 5

Why is their a dip in ionisation energy between
group 2 -> 3 ?

(3 points)

Answer 5

electron removed is going from 2s -> 2p
↑ in atomic radius = ↓ attraction

Question 6

Why is their a dip in ionisation energy between group 5 -> 6 ?

Answer 6

Group 5 has 3 electrons in 2p orbital
Group 6 has 4 electrons in 2p orbital
↑ repulsion at Group 6 as electron shares orbital

Question 7

Why is there a dip in ionisation energy when going from down period?

Answer 7

1. ↑ atomic radius
2. ↑ shielding
3. both factors outwiegh ↑ nuclear charge

Question 8

What is the pattern in ionisation energies down the group + WHY?

Answer 8

↓ down the group
1. gain a shell
2. shielding increases
3. atomic radius increases
4. both factors outweigh increased nuclear charge

Question 9

How to predict group through successive ionisation energies ?

Answer 9

A peak in ionisation energies = no. of electron in outershell = group no.

Question 10

Definition of ionisation energy

Answer 10

Energy required to remove 1 mol of electrons from 1 mol of gaseous atoms to form 1 mol of gaseous 1+ ions

Question 11

Define Metallic bonding

Answer 11

The electrostatic attraction between metal cation and sea of delocalised electron

Question 12

What is the structure of all metal ?

Answer 12

A gaint metallic lattice structure

Question 13

4 Properties of metallic srtucture

Answer 13

1. ↑ MP and BP
2. ↑ electrical conductivity
3. Insoluble
4. malleable

Question 14

Define gaint covalent structure

Answer 14

A network of atoms bonded by strong covalent bond

Question 15

Properties of gaint covalent structure

Answer 15

1. high M.P. and B.P.
2. Insoluble

Question 16

electrical conductivity of graphite and diamond

Answer 16

Graphite - conducts
[only 3 covalent bond/carbon,1 mobile]
Diamond - Doesn’t
[ 4 covalent bonds, no mobile electron]

Question 17

describle the trend of B.P. across period

Answer 17

Group 1-4 = gradual increase [gaint structure]
Group 4-5 = sudden drop
group 5-8 = neglictible difference [simple molecular]

Question 19

Reactivity of group 2 down the group

Answer 19

INCREASES
1. ↑atomic radius
2. ↑shielding
3. ↓energy required to remove an electron

Question 20

What happens when group 2 reacts

Answer 20

oxidised to form 2+ ions

Question 21

What do Group 2 form when reacted to water

Answer 21

metal hydroxide and hydrogen

Question 22

how does solubility changes down the group 2 ? and WHY?

Answer 22

INCREASES solubility and pH
1. As they are more reactive down the group
2. particles are more likely to be attracted to polared molecules
3. hence more soluble

Question 23

how does pH changes down the group 2 ? and WHY?

Answer 23

INCREASES1. as they are mroe soluble down the group 2. more group 2 oxides reacts and form more OH ions 3. hence conc of OH increases

Question 24

What is the action of water on group 2 oxides

Answer 24

metal oxides + water -> metal 2+ + 2 OH -

Question 25

2 uses of group 2 compounds

Answer 25

1. milk of magnesia (Mg(oH)2) - neutralise stomach acid
2. Calcium hydroxide neturalise acidic soil

Question 26

What do all pure halogens exists in?

Answer 26

diatomic molecules

Question 27

Trend of BP down the group 7?

Answer 27

Increases down the group
1. ↑ no. of electrons
2. ↑ London forces
3. ↑ electrons = ↑ london forces

Question 28

Color of halogens in water

Answer 28

Cl - pale green
Br - orange
I - brown

Question 29

which halogen have a different colour in organic solvent and what colour ?

Answer 29

In cyclohexane : Iodine - violet

Question 30

Reactivity of Halogens down the group

Answer 30

Decreases
1. ↑ atomic radius’
2. ↑ shielding
3. ↓ nuclear attraction to GAIN ELECTRON

Question 31

Rule for halogen displacement

Answer 31

More reactive displaces less reactive

Question 32

formulae for Bleach

Answer 32

NaClO

Question 33

formula for choric acid

Answer 33

HClO

Question 34

Pros and cons of use of Chlorine in water treatment

Answer 34

Pros
* kills bacteria (e.g. Cholera)

Cons
* irritant in small amount
* fatal in large amounts
* chlorinated hydrocarbon may form

Question 35

How does atomic radius increases

Answer 35

down and left

Question 36

How does 1st ionisation increases across period?

+ explain (4)

Answer 36

1. ↑ nuclear charge
2. dist. from nucleus = k
3. shielding = k
4. ↓ atomic radius

↑ attraction so ↑

Question 37

Colour of iodine in solution

Answer 37

Yellow - orange

Question 38

Colour of bromine in solution

Answer 38

Orange

Question 39

Colour of chlorine in solution

Answer 39

Pale green