Group 2

Question 1

Write an equation for the first ionization energy of magnesium

Answer 1

Mg-> Mg+ + e-

Question 2

Explain the trend in ionization energies across period 3 on the periodic table

Answer 2

• First ionization energy increases across group 3 because:
• Of increased nuclear charge
• Decreased atomic radius
And same electron shielding which means more energy is needed to remove the first electron

However
• Dips at Al because outer electron is in a 3p orbital, higher energy than 3s orbital which means less energy needed to remove an electron
• Dips at S because one 3p orbital contains two electrons -> repulsion between paired electrons-> less energy needed to remove one

Question 3

What happens to the first ionization energy as you go down 2 why?!

Answer 3

• Decreases because: number of filled electron shells increases down the group
• Increased shielding
• Increased atomic radius -> weaker force between outer electron and nucleus which means less energy needed to remove the electron

Question 4

How does reactivity with water change as you go down group 2

Answer 4

• Increases
• Because outer electrons are further from the nucleus and more electron shielding so electrons are lost more easily

Question 5

Give the equation for the reaction of barium and water

Answer 5

• Ba(s) + 2H2O(l) -> Ba(OH)2(aq) + H2(g)

Question 6

Write an equation for the reaction of Magnesium and steam

Answer 6

Mg(s) + H2O(g) -> MgO(s) + H2(g)

Question 7

What is the trend in hydroxide solubility down group 2

Answer 7

• Increases down the group
• Mg(OH)2 is almost insoluble
• Ba(OH)2 creates a strong alkaline solution

Question 8

What is the trend in sulphate solubility down group 2

Answer 8

• Decreases down the group
• MgSO4 is soluble
• BaSO4 is insoluble

Question 9

What is trend in melting point down group 2 and why?

Answer 9

• Decreases down the group
• Because sea of delocalized electrons is further from the positive charge of the nucleus
• Weaker metallic bonds/ forces of attraction which take less energy to weaken

Question 10

What is the trend in atomic radius in group 2

Answer 10

• Increases as there are more occupied electron shells down the group

Question 11

What are flue gases?

Answer 11

• Gases produced by power stations which are harmful to the environment

Question 12

How can CaO or CaCO3 be used to remove flue gases? Write equations

Answer 12

• CaCO3(s) + SO2(g) -> CaSO3(s) + CO2 (g)
• CaO (s) + SO2 (g) -> CaSO3 (s)

Question 13

What is Ca(OH)2 used for? Write an equation related to one of its uses

Answer 13

• Used to neutralize soil
• Ca(OH)2 (aq) + 2HCl (aq) -> 2H2O (l) + CaCl2 (aq)
• Used in agriculture to neutralize acid soil

Question 14

What is Mg(OH)2 used for?

Answer 14

Milk of magnesia- antacid to treat digestion, heartburn, wind e.t.c
• Used in some indigestion tablets as an antacid

Question 15

What is a use of BaSO4? Why is it safe?

Answer 15

• In barium meals to outline gut in x-rays
• Ba2+ is toxic but is fine as barium sulphate is insoluble

Question 16

How can BaCl be used to test for sulphate ions

Answer 16

• Add to sample with HCl, white ppt will form if sulphate ions are present
• Ba2+ + SO4 2- -> BaSO4

Question 17

What happens when group 2 elements react with water

Answer 17

• They are oxidized
• from a state of 0 to +2 forming M+ ions

Question 18

Explain the solubility trends in Group 2

Answer 18

• They depend on the compound anion
• Compounds of Group 2 elements that only contain singly charged negative ions (OH-) increase in solubility down the group
• Compounds with doubly charged negative ions (SO42-) decrease in solubility down the group

Question 19

What are Group 3 compounds mostly used for?

Answer 19

Neutralizing acids

Question 20

Give the equation of neutralization

Answer 20

H+ + OH- -> H2O

Question 21

Write out the test for sulfate ions

Answer 21

• Ba2+ (aq) + SO42-(aq) -> BaSO4(s)
• BaCl2(aq) + FeSO4(aq)-> BaSO4(s) + FeCl2(aq)

Question 22

What is an antacid?

Answer 22

A substance that neutralizes excess stomach acid

Question 23

How does barium sulfate in barium meals work?

Answer 23

• Barium Sulfate is opaque to X-rays, they won’t pass through it.
• A patient swallows barium meal which is a suspension of barium sulfate.
• The barium sulfate coats the tissues, making them show up on the X-rays, showing the structure of the organs

Question 24

Describe how magnesium is used in the extraction of titanium

Answer 24

• The main titanium ore, titanium(IV) oxide (TiO2) is first converted to titanium(IV) chloride (TiCl4) by heating it with carbon in a steam of chlorine gas.
• The titanium chloride is then purified by fractional distillation, before being reduced by magnesium in a furnace at almost 1000*C

Question 25

Describe how Calcium oxide and calcium carbonate remove sulfur dioxide

Answer 25

• Burning fossil fuels to produce electricity also produces sulfur dioxide which polluted the atmosphere
• Acidic sulfur dioxide can be removed from flue gases by reacting with an alkali - wet scrubbing
• Powdered calcium oxide (lime CaO) and calcium carbonate (limestone) can be used for this
• A slurry is made by mixing the calcium and cure or calcium carbonate with water. It’s then sprayed into the flue gases. The sulfur dioxide reacts with the alkaline slurry and produces a solid waste product, calcium sulfite

Question 26

state one observation when magnesium reacts with steam

Answer 26

white light

Question 27

A student is provided with samples of three nickel compounds.
One sample is nickel(II)bromide, another is nickel(II) sulfate and the third is nickel(II) carbonate. The student doesn’t know which sample is which.
Describe the tests that the student could carry out to identify the anion (negative ion) in each sample, and write equations for any reactions.

Answer 27

TEST FOR ANIONS
- Carbonate test: Add HNO3/HCL/H2SO4/H+, fizzing/forms CO2(g), carbonate identified
- Sulfate test: Add Ba(NO3)2 or BaCl2(aq), white precipitate, sulfate identified
- Bromide test: Add AgNO3(aq), Cream precipitate, bromide identified

EQUATIONS