group 2

Question 1

trend in atomic radius down the group

Answer 1

increases down group
more shells of electrons
makes atom bigger

Question 2

trend in melting points down the group

Answer 2

decreases
metallic bonding weakens as atomic size increases
distance between delocalised electrons + positive ions increases
so electrostatic forces weaken

Question 3

trend in 1st ionisation energy

Answer 3

outer electrons held weakly
successively further from nucleus
outer electrons more shielded from attraction of nucleus
by repelling inner shells of electrons

Question 4

trend in reactivity down group 2

Answer 4

increases

Question 5

observation of Mg and oxygen

Answer 5

bright white flame

Question 6

equation for Mg and oxygen

Answer 6

2Mg + O2 🠮 2MgO

Question 7

what is MgO

Answer 7

white solid
with high melting point
due to ionic bonding

Question 8

what does Mg in steam produce + observation

Answer 8

Mg (s) + H2O (g) 🠮 MgO (s) + H2 (g)

burns with bright white flame

Question 9

what does Mg in warm water produce + observation

Answer 9

Mg + 2 H2O 🠮 Mg(OH)2 + H2
no flame
much slower reaction

Question 10

what do the other g2 metals react with to form hydroxides

Answer 10

cold water

Question 11

trend in reactivity for cold water + g2 metals

Answer 11

increasing vigour down group

Question 12

observations of G2 and cold water + changes down the group

Answer 12

🠮fizzing, (more vigorous down group)
🠮the metal dissolving, (faster down group)
🠮the solution heating up (more down group)
🠮with calcium a white precipitate appearing
(less precipitate forms down group with
other metals)

Question 13

what are the steps in extracting titanium

Answer 13

1. TiO2(solid) converted to TiCl4(liquid) at 900°C:
   2.TiCl4 purified by fractional distillation in argon
   atmosphere.
2. Ti is extracted by Mg in argon atmosphere at 500°C

Question 14

write the two equations for converting TiO2 to Ti

Answer 14

TiO2 + 2 Cl2 + 2 C 🠮TiCl4 + 2 CO

TiCl4 + 2Mg🠮 Ti + 2 MgCl2

Question 15

why is Mg used to extract Titanium

Answer 15

it is a more reactive metal

Question 16

trend in solubility of G2 Hydroxides

Answer 16

increases down group

Mg(OH)2 - sparingly soluble

Question 17

ionic equation for Mg(OH)2

Answer 17

Mg2+(aq) + 2OH-(aq) 🠮 Mg(OH)2(s)

Question 18

use of Mg(OH)2 in medicine

Answer 18

to neutralise excess stomach acid

treat constipation

Question 19

use of Ca(OH)2 in medicine

Answer 19

used in agriculture
to neutralise acidic soils
essential for good crop production and maintaining the food supply

Question 20

trend in G2 sulfates down the group

Answer 20

decreasing solubility

Question 21

full equation of SrSO4

Answer 21

SrCl2(aq) + Na2SO4 (aq) 🠮 2NaCl (aq) + SrSO4 (s)

Question 22

ionic equation of SrSO4

Answer 22

Sr2+(aq) + SO4 2-(aq) 🠮SrSO4(s)

Question 23

how is BaSO4 used in medicine

Answer 23

Barium meal
Ba absorbs x-rays
low solubility - not absorbed into blood - safe to use

Question 24

what reagent is used to test for sulfate ions

Answer 24

BaCl2 solution acidified with HCL

Question 25

what is the positive result for test for sulfate ions

Answer 25

white ppt of BaSO4

Question 26

ionic equation of Ba and SO4

Answer 26

Ba2+ (aq) + SO42-(aq) 🠮 BaSO4(s)

Question 27

why is Hcl used in a test for sulfate ions

Answer 27

to react with carbonate impurities

2HCl + Na2CO3 🠮 2NaCl + H2O + CO2

Question 28

draw the diagrams for filtration

Answer 28

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