Inorganic: Group 2/Group 7

Question 1

What are three physical properties that have a trend in group 2?

Answer 1

• atomic radius
• first ionisation energy
• melting point

Question 2

What is the trend for atomic radius in group 2?

Answer 2

as you go down the group, the atomic radius increases

-extra energy shells as you go down

Question 3

What is the trend for first ionisation energy in group 2?

Answer 3

first ionisation energy decreases down the group

• extra electron shells as you go down, so extra inner e⁻ shields outer electrons from attraction of the nucleus
• more energy shells increases distance from the nuclear, which decreases nuclear attraction, so it is easier to lose outer e⁻

Question 4

What is the GENERAL trend for melting point in group 2 ?

Answer 4

melting point GENERALLY decreases down the group. Group 2 metals normally form metallic structures

• down the group, metal ions get bigger
• BUT charge and no. of delocalised e⁻ stays the same
• larger ionic radius, reduced attraction
• takes less energy to break bonds

Question 5

What type of bonding do group 2 metals normally form?

Answer 5

metallic bonds

Question 6

What is the trend for reactivity of group 2 metals?

Answer 6

down the group, they get more reactive

• because they have a larger atomic radius os more distance and more inner shielding e⁻
• so easier to lose e⁻
• more reactive

Question 7

What is the exception for trend of melting point of group 2 metals?

Answer 7

magnesium

it goes underneath line of best fit

Question 8

Are all nitrates soluble?

Answer 8

Yes, all nitrates are soluble

there are no exceptions

Question 9

Are all sulfates soluble?

Answer 9

most sulfates are soluble

exceptions:lead sulfate, barium sulfate, calcium sulfate

Question 10

Are all chlorides, bromides and iodides soluble?

Answer 10

most of them are soluble

exceptions: SILVER chloride/bromide/iodide, LEAD chloride/bromide/iodide —-insoluble

Question 11

Are all carbonates soluble?

Answer 11

most carbonates are insoluble

exceptions: sodium carbonate, potassium carbonate, ammonium carbonate

Question 12

What are the group 2 reactions with water?

Answer 12

they form a metal hydroxide and hydrogen
the reaction gets more vigorous down the group
metal + water —–> metal hydroxide + hydrogen
Mg + water ——> MgO + H₂

Question 13

What is the trend for solubilities of the hydroxides of group 2 metals?

Answer 13

as you go down the group, solubility increases
Mg(least soluble)
Ba (most soluble)

Question 14

What is the trend for solubilities of the sulfates of group 2 metals?

Answer 14

as you go down the group, solubility decreases
Mg (most soluble)
Ba (least soluble)

Question 15

Why is acidified barium chloride used to test for sulfate ions?

Answer 15

this is because it forms barium sulfate because it is one of the few sulfate compounds that is insoluble, so you can see the product
it is acidified because the acid removes any traces of carbonate ions (that would have also produced a white precipitate)

Question 16

What is the use of magnesium in the extraction of titanium?

Answer 16

magnesium is used as the reducing agent
titanium is extracted from its ore as TiO₂ and cannot be reduced using carbon— because it forms TiC (carbide), which forms a brittle metal
so instead, they form TiCl₄, and then reduce with Mg

Question 17

What is the use of MgOH is medicine?

Answer 17

-increases water in the intestines - to induce bowel movements and relieve constipation
-used as an antacid to relieve indigestion and heartburn
(antacid- neutralises excess stomach acid)

Question 18

What is the use Ca(OH)₂ in agriculture?

Answer 18

used to neutralise acid in soils for plant growth

Question 19

What are flue gases?

Answer 19

gases emitted by industrial exhausts and chimneys

Question 20

What is the use of CaO or CaCO₃ in removal of SO₂ from flue gases?

Answer 20

burning fossil fuels to generate electricity produces sulfur dioxide which is a pollutant, this can be removed by reacting it with an alkali (wet scrubbing)
CaO and CaCO₃ are sprayed onto the gases
produces calcium sulfate

Question 21

What is wet scrubbing?

Answer 21

reacting the flue gases with an alkali to remove SO₂

Question 22

What is the use of BaSO₄ in medicine?

Answer 22

BaSO₄ is insoluble, it is opaque to X-rays (it shows up on an X-ray)
Used in Barium meals, to help diagnose problems with stomach, oesophagus or intestines because the BaSO₄
coats the soft tissues, making them show on the X-rays

Question 23

Why can you not use other barium compounds for barium meals?

Answer 23

this is because other barium compounds would produce a solution which is poisonous but barium sulfate is insoluble so it forms a suspension, not a solution

Question 24

What is the colour and state of fluorine at room temperature?

Answer 24

it is a pale yellow gas

Question 25

What is the colour and state of chlorine at room temperature?

Answer 25

it is a green gas

Question 26

What is the colour and state of bromine at room temperature?

Answer 26

red-brown liquid

Question 27

What is the colour and state of iodine at room temperature?

Answer 27

it is a grey/black solid

Question 28

What is the trend for the boiling point of the halogens?

Answer 28

boiling point increases down the group due to the increasing strength of the van de Waal forces (type of IMF ) as the size of the molecule increases so the energy required to overcome the forces increases

Question 29

What is the trend for electronegativity in halogens?

Answer 29

electronegativity decreases down the group
larger atoms attract electrons less easily than smaller ones. outer electrons are further away from the nucleus and there are more inner shielding e⁻

Question 30

What is electronegativity?

Answer 30

it is the ability to attract bonding electrons in a covalent bond
higher the number, the better it is to attract bonding electrons