group 2 metals (inorganic)

Question 1

equation for the first ionisation energy of magnesium

Answer 1

Mg(g) > Mg+(g) + e-

Question 2

Why does ionisation energy increase across group 3?

Answer 2

Increased nuclear charge, decreased atomic radius and same electron shielding means more energy is needed to remove the first electron.

Question 3

Why is there a dip in ionisation energy at Al?

Answer 3

Outer electron is in a 3p orbital which is higher than 3s orbital so there is less energy needed to remove the electron

Question 4

Why is there a dip in ionisation energy at S?

Answer 4

one 3p orbital contains 2 electrons > repulsion between paired electrons > less energy needed to remove one

Question 5

What happens to the first ionisation energy as you go down group 2? Why?

Answer 5

Decreases because of increased shielding, increased atomic radius > weaker force between the outer electron and nucleus > less energy needed to remove electron

Question 6

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

Answer 6

Increases (Mg least > Ba most) because outer electrons further from nucleus and more electron shielding so electrons are lost more easily

Question 7

equation for reaction of barium and water

Answer 7

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

Question 8

equation for magnesium and steam

Answer 8

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

Question 9

What is trend in hydroxide solubility going down group 2?

Answer 9

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

Question 10

What is the trend in sulfate solubility down group 2?

Answer 10

Decreases down group. MgSO4 is soluble, BaSO4 is insoluble

Question 11

What is the trend in melting point down group 2? Why?

Answer 11

Decreases down the group because the sea of delocalised electrons is further from the positive charge of the nucleus > weaker metallic bonds/forces of attraction which take less energy to weaken

Question 12

What is the trend in atomic radius down group 2?

Answer 12

Increases as there are more occupied electron shells down the group

Question 13

Write the equation for the extraction of titanium using magnesium

Answer 13

TiCl4(l) + 2Mg(s) > 2MgCl2(s) + Ti(s)

Question 14

What are flue gases?

Answer 14

Gases produced by power stations which are harmful to the environment

Question 15

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

Answer 15

CaCO3(s) + SO2(g) > CaSO3(s) + CO2(g)

CaO(s) + SO2(g) > CaSO3(s)

Question 16

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

Answer 16

Used to neutralise soil
Ca(OH)2(aq) + 2HCl(aq) > 2H2O(l) + CaCl2(aq)

Question 17

What is Mg(OH)2 used for?

Answer 17

laxative, neutralises stomach acid, treat indigestion

Question 18

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

Answer 18

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

Question 19

How can BaCl be used to test for sulfate ions?

Answer 19

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