Group 2

What ion do they form and how?

Lose 2 electrons to form 2+ ions to achieve a full outer shell.

Atomic radius down the group

Increases due to increasing electron shells

Reactivity down the group

Increases due to increased shielding

1st IE down the group

Decreases due to increased size/ shielding

What is shielding?

More shells between the outer electrons and the nucleus decreases nuclear attraction making outer electrons easier to remove

Ionisation energy down the group

Decreases due to greater atomic radius and more shielding

Melting point down the group

Decreases as the metal ions get larger down the group so the attractive forces have to act over a greater distance

General reaction with water

Redox reaction to produce a metal hydroxide and hydrogen. The metal hydroxide forms as an alkaline solution

Describe the reaction of magnesium in water

Reacts very slowly

What does magnesium + water produce

Magnesium hydroxide

Describe the reaction with magnesium in steam

Provides more energy than water so it burns with a bright white flame

What does magnesium + steam produce?

Hydrogen and magnesium oxide

What colour is magnesium oxide?

White powder

How do the group 2 elements (except magnesium) react with water including observations and precipitates fomed

Can react with cold water increasingly vigorously down the group

Observations include: fizzing, metal dissolving, solution heating up

Calcium produces a white ppt, less and less forms as you go down the group

What is calcium hydroxide used for and why?

Used in agriculture to neutralise acidic soils

What can aqueous calcium hydroxide be used for?

Limewater - tests for carbon dioxide as it turns cloudy because calcium carbonate is produced

Solubility of group 2 hydroxides down the group

Increases

What is magnesium hydroxide used as and why?

An antacid because it is alkaline and can neutralise acids. It is also the least soluble group 2 hydroxide.

Solubility of group 2 sulfates down the group

Decreases

What is barium sulfate used for and why?

Barium meals/ X-ray. It is toxic if it enters the bloodstream however this does not happen because it is insoluble.

Barium sulfate colour

White precipitate

What is barium chloride used for?

To test for sulfate ions as it reacts to form barium sulfate (white ppt)

What is magnesium used for and why?

The extraction of titanium from titanium chloride via a displacement reaction

Equation between titanium chloride and magnesium

What is calcium oxide used for and why?

Reacts with sulfur dioxide to remove it from factory pollutants and prevent it being released into the atmosphere

Calcium oxide + sulfur dioxide equation