Group 2 Metals

Question 1

What are the group 2 elements referred to as?

Answer 1

• alkaline earth metals

Question 2

Summarise the trend in melting point going down group 2

Answer 2

• electrons become further away from positive nuclei
• decrease slightly going down the group
• magnesium is an exception but not simply explainable

Question 3

What compounds do group 2 metals form with -OH (hydroxide groups)?

Answer 3

• Mg(OH)2 is a precipitate which is almost insoluble (milk of magnesia)
• Ca(OH)2 is a sparingly soluble precipitate (solution used as lime water and slaked lime)
• Sr(OH)2 is soluble
• Ba(OH)2 is soluble and dissolves to produce a very alkaline solution

Question 4

What compounds do group 2 metals form with -SO4 (sulphate groups)?

Answer 4

• MgSO4 which is soluble
• CaSO4 is a thin white precipitate
• SrSO4 is a white precipitate
• BaSO4 is a thick white precipitate that’s very insoluble, this makes it safe to ingest as a barium meal, which outlines the gut in x rays

Question 5

How is titanium extracted from its ore?

Answer 5

• titanium oxide reacted with chlorine and carbon (coke)
• forms TiCl4 (and CO)
• reacted with magnesium
• displaced:
• TiCl4 + 2Mg –> 2MgCl2 + Ti

Question 6

How do the Group 2 metals react with water?

Answer 6

• magnesium very slowly w cold water but rapidly with steam
• the rest increase in reactivity down the group
• so react vigorously even with cold water