EL 8

Question 1

Explain why FIE increases as you go down a group

Answer 1

• adding a shell of electrons each time (bigger radius)
• greater electron shielding
• greater shielding and radius negates effect of larger nucleus
  Lesss energy required to remove outer electrons
• decreasing the FIE

Question 2

Explain why FIE increases as you go along a period

Answer 2

• Increased number of protons
• Same number of shells
• Stronger attraction between the nucleus and outer electrons
• Therefore more energy is required to remove the outer electrons
• INCREASING FIE

Question 3

What is ionisation?

Answer 3

The removal of one or more electrons

Question 4

What is ionisation enthalpy?

Answer 4

The energy needed to remove 1 electron from each atom in 1 mole of gaseous atoms to form 1 mole of gaseous 1+ ions

Question 5

First ionisation of oxygen equation

Answer 5

O -> O+ + e-

Question 6

The lower the ionisation enthalpy ____

Answer 6

The easier it is to remove an outer electron and form an ion

Question 7

What 3 things affect the size of ionisation enthalpies?

Answer 7

• Atomic radius
• Nuclear charge
• Electron shielding

Question 8

Why does an atom with a low atomic radius have a low ionisation enthalpy?

Answer 8

The further the outer shell electrons are from the positive nucleus, the leads they’ll be attracted towards the nucleus

Question 9

Why does an atom with a high nuclear charge have a high ionisation enthalpy?

Answer 9

The more protons in the nucleus, the more it’ll attract the outer electrons
So it’ll be harder to remove the electrons

Question 10

Why does an atom with a high electron shielding have a low ionisation enthalpy?

Answer 10

More inner electrons means more shielding
And this means the attractive force between the electrons and positive nucleus will be more intercepted

Question 11

Why does first ionisation enthalpy decrease as you go down group 1 and 2?

Answer 11

1) as you go down the group, the outer electrons are in shells further from the nucleus
SO they are attracted to the nucleus less
2) the amount of shielding also increases because there are more filled inner shells
SO greater interception
SO less attraction for the outer shell electrons

Question 12

Why does ionization enthalpy increase as you go across a period?

Answer 12

Because the number of protons is increasing
So outer electrons are attracted more strongly to the nucleus

Question 13

Why do S-block metals have low ionisation enthalpies?

Answer 13

• They have low nuclear charges
• so the outer electron is less attracted to the nucleus and easier to lose

Question 14

Why do P-block metals have higher ionisation enthalpies?

Answer 14

• They have more protons so higher nuclear charges
• So greater attraction between the nucleus and the outer electron

Question 15

Group 2 element + water -> ?

Answer 15

Metal hydroxide + hydrogen

Question 16

Group 2 element + oxygen -> ?

Answer 16

oxides (solid white precipitate)

Question 17

What happens to reactivity as you go down group 2?

Answer 17

Increases

Question 18

What type of elements are group 2 hydroxides and oxides?

Answer 18

Bases

Question 19

Why do group 2 hydroxides form alkaline solutions in water?

Answer 19

The metal hydroxides dissolve and the hydroxide ions make these solutions strongly alkaline

Question 20

Group 2 oxide OR hydroxide + acid ->

Answer 20

Salt + water

Question 21

What is thermal decomposition?

Answer 21

When a substance breaks down when heated

Question 22

What do group 2 carbonates decompose to form?

Answer 22

Metal oxide + CO2

Question 23

What happens to thermal stability of carbonates as you move down group?

Answer 23

It increases

Question 24

What doe sit mean if a substance is more thermally stable?

Answer 24

It takes more heat to break it down

Question 25

Why would a carbonate ion be less stable?

Answer 25

• the cation is further down group 2 so larger so has lower charge density
• so distortion is smaller as the cation polarises it less
• so it is more stable

Question 26

What happens to metallicness as you go down a group?

Answer 26

Increases

Question 27

What happens as elements get more metallic?

Answer 27

They get more reactive

Question 28

What happens to metallicness across a period?

Answer 28

Decreases

Question 29

3 group 2 properties

Answer 29

Reasonably high MP & BP
Low densities
From colourless compounds

Question 30

What is 1st ionisation enthalpy?

Answer 30

A measure of how easily an atom loses an electron to form an ion

Question 31

What are successive ionization enthalpies?

Answer 31

Enthalpies after the first ionization enthalpy

Question 32

Why is each successive IE larger than the one before?

Answer 32

The distance of each electron from the nucleus decrease slightly so the nuclear attraction increases

Question 33

What happens to groups 2 elements in redox reactions?

Answer 33

• They are oxidized
• When they are used as strong reducing agents

Question 34

Group 2 + water ->

Answer 34

Hydroxides + hydrogen

Question 35

What is charge density?

Answer 35

A measure of the concentration of charge on the cation

Question 36

Base sate symbol

Answer 36

S

Question 37

Alkali state symbol

Answer 37

Aq

Question 38

What happens to solubility of carbonates as you go down group 2?

Answer 38

Less soluble

Question 39

What happens to solubility of hydroxide as you go down group 2 and why?

Answer 39

Increases

As size of metal ion increases
So less attraction between metal cation and OH- anion in the hydroxide
Which makes it easier for water molecules to break up the lattice

Question 40

What are 2 uses of group 2 hydroxides?

Answer 40

Calcium hydroxide is used by farmers and gardeners as “lime” to neutralize acidic soil

Magnesium hydroxide is used in “milk of magnesia” to relieve indigestion by neutralizing stomach acidic