Group II Elements

Learning Objectives CIE• Describe the reactions of the elements of group II with

oxygen and water• Describe the behavior of the oxides with water• Describe the thermal decomposition of the nitrates and

carbonates in terms of equations• Interpret and make predictions from the trends in physical

and chemical properties of the elements and their compounds

• Explain the use of magnesium oxide as a refractory lining material and carbonate as a building material

• Describe the use of lime in agriculture

Learning Outcomes Students should be able to work in groups to• Gather and use the information from various

sources to find answers to the questions on the following slides

• Share their answers with the rest of the class through posters prepared on the spot and explain the concepts applied

• Provide feedback to their class mates if their posters and explanations were helpful in effective learning

Questions Explaina) How do you expect the ionic radii of group II elements to

compare with their corresponding atoms?b) How do you expect the ionic radii of group II elements to vary

down the group?c) How do you expect the reactivity of group II elements to vary

down the group?d) How do you expect the solubility of group II Oxides to vary down

the group?e) Group II carbonates and nitrates decompose on heating. What is

the trend in thermal decomposition down the group?f) If there are any uses of group II compounds. 

Group VII Elements

Learning Objectives CIE• Explain the trend in atomic size down group VII• Describe the trends in volatility and color of halogens

down the group• Explain how size of molecule affects strength of Van

der waals forces and its effect on boiling point• Describe the relative reactivity of elements as

oxidizing agents• Describe and explain reactions of halogens with

hydrogen gas• Explain trend in thermal stability of hydrides in terms

of bond length and bond energy

Learning Objectives CIE• Describe and explain the reactions of halide ions with (i) aqueous silver ions followed by aqueous ammonia (ii) Concentrated sulphuric acid• Recall diagram illustrating the manufacture of chlorine from

brine by diaphragm cell • Write chemical equations for the reactions between cold and hot

aqueous sodium hydroxide with chlorine• Explain the term disproportionation in terms of changes in

oxidation numbers• Explain use of chlorine in water purification• List the uses of chlorine, NaClO, NaClO3, NaOH• Recognize the industrial importance and environmental

significance of the halogens and their compounds.

Questionsa) Draw a chart to show the trend in melting points, boiling points,

color, physical states and electro negativities down group VII elements.

b) Astatine lies at the bottom of the group. What do you expect its physical state and color to be?

c) Explain the trend in the reactivity of group VII elements down the group.

d) How can you demonstrate the trend in oxidizing abilities of halogens down the group?

e) Describe what would be observed when halogens react with hydrogen?

f) Using bond energy values in data booklet explain the trend in the thermal stabilities of hydrogen halides.

g) Describe the reactions of halide ions that you carried out in the lab.