Complete the table below to estimate the boiling point and atomic radius of caesium. Comment also on the reactivity of potassium and caesium with water. Group I metal Density / g / Cm 3 Radius of metal atom nm Boiling point ° C Reactivity with water Sodium 0 . 97 0 . 191 883 Floats and fizzes quickly on the surface, disappears gradually and does not burst into flame. Potassium 0 . 86 0 . 235 760 _____ Rubidium 1 . 53 0 . 250 686 Reacts instantaneously, fizzes and burst into flame then spits violently and may explode. Caesium 1 . 88 _____ _____ _____

Reactivity of potassium with water: Potassium is the third alkali metal and its reaction with water is more vigorous than sodium. It floats on the surface of the water and fizzes vigorously. It disappears and catches fire with a lilac flame. Reactivity of caesium with water: Caesium is the fourth alkali metal which is more reactive than the metals above it in the periodic table. It reacts vigorously with water and explodes. It can also shatter the container. The radius of the atom is the distance between the outermost shell and the centre of the nucleus. As moving down the group we can see that the atomic radius is increasing and the boiling point is decreasing. Thus, the atomic radium of caesium atom is 0 . 265 nm , and its boiling point is 671 ° C . The complete table is as follows: Group I metal Density / g / Cm 3 Radius of metal atom nm Boiling point ° C Reactivity with water Sodium 0 . 97 0 . 191 883 Floats and fizzes quickly on the surface, disappears gradually and does not burst into flame. Potassium 0 . 86 0 . 235 760 It floats on the surface of the water and fizzes vigorously. It disappears and catches fire with a lilac flame. Rubidium 1 . 53 0 . 250 686 Reacts instantaneously, fizzes and burst into flame then spits violently and may explode. Caesium 1 . 88 0 . 265 671 It reacts vigorously with water and explodes. It can also shatter the container.

In each of the experiments below, a piece of metal is placed in a solution of a metal salt. Complete the table of observations. At start Colour of metal grey _____ silver-coloured silver-coloured _____ Colour of solution colourless _____ blue blue colourless At finish Colour of metal coated with silver coloured crystals _____ coated with brown solid silver-coloured coated with silver-coloured crystals Colour of solution colourless _____ colourless blue _____

The reactive metals when dipped in the solutions of the less reactive metals, they undergo a displacement reaction. Zinc is a grey coloured metal which is more reactive than tin and hence, it replaces it from tin chloride solution. Tin gets deposited on zinc as a silver coloured metal and leaving the solution colourless due to the formation of zinc chloride. Zinc is a grey coloured metal which is more reactive than copper and hence, it replaces it from copper sulphate solution. Copper gets deposited on zinc as a brown coloured metal and leaving the solution colourless due to the formation of zinc sulphate. Tin is a silver coloured metal which is more reactive than copper and hence, it replaces it from copper sulphate solution. Copper gets deposited on tin as a brown coloured metal and leaving the solution colourless due to the formation of tin sulphate. Silver is a silver coloured metal which is less reactive than copper and hence, it does not displace it from copper sulphate solution. Therefore, the colour of the solution and the metal remain intact and no changes can be observed. Copper is a brown coloured metal which is more reactive than silver and hence, it replaces it from silver nitrate solution. Copper gets deposited on silver as a brown coating and leaving the solution blue due to the formation of copper nitrate. At start Colour of metal grey grey silver-coloured silver-coloured brown Colour of solution colourless blue blue blue colourless At finish Colour of metal Coated with silver coloured crystals Coated with brown solid Coated with brown solid silver-coloured Coated with silver-coloured crystals Colour of solution colourless colourless colourless blue blue

MEDIUM

Upper Secondary-IGCSE

IMPORTANT

Earn 100

Brass is an alloy of copper and zinc. It is used to make brass musical instruments and to make electrical connectors and plugs. There are two main types of brass: $60 : 40$ and $70 : 30$ copper to zinc. The larger the amount ot zinc, the harder and stronger the alloy is.

Suggest which alloy is used for each of the purposes mentioned above. Give a reason for your answers.

Important Questions on Patterns and Properties of Metals

MEDIUM

Upper Secondary-IGCSE

IMPORTANT

Cambridge IGCSE Chemistry Workbook 4th Edition>Chapter 8 - Patterns and Properties of Metals>Exercise 8.1>Q a

Caesium is an alkali metal. It is in Group I of the Periodic table.

State two physical properties of caesium.

EASY

Upper Secondary-IGCSE

IMPORTANT

Cambridge IGCSE Chemistry Workbook 4th Edition>Chapter 8 - Patterns and Properties of Metals>Exercise 8.1>Q b

Caesium is an alkali metal. It is in Group I of the Periodic table.

State the number of electrons in the outer shell of a caesium atom.

HARD

Upper Secondary-IGCSE

IMPORTANT

Cambridge IGCSE Chemistry Workbook 4th Edition>Chapter 8 - Patterns and Properties of Metals>Exercise 8.1>Q c

Complete the table below to estimate the boiling point and atomic radius of caesium. Comment also on the reactivity of potassium and caesium with water.

Group I metal	Density $/ g / {Cm}^{3}$	Radius of metal atom $(nm)$	Boiling point $(° C)$	Reactivity with water
Sodium	$0.97$	$0.191$	$883$	Floats and fizzes quickly on the surface, disappears gradually and does not burst into flame.
Potassium	$0.86$	$0.235$	$760$	_____
Rubidium	$1.53$	$0.250$	$686$	Reacts instantaneously, fizzes and burst into flame then spits violently and may explode.
Caesium	$1.88$	_____	_____	_____

EASY

Upper Secondary-IGCSE

IMPORTANT

Cambridge IGCSE Chemistry Workbook 4th Edition>Chapter 8 - Patterns and Properties of Metals>Exercise 8.1>Q d

Write the word equation for the reaction of caesium with water.

EASY

Upper Secondary-IGCSE

IMPORTANT

Cambridge IGCSE Chemistry Workbook 4th Edition>Chapter 8 - Patterns and Properties of Metals>Exercise 8.2>Q a

Magnesium reacts very slowly indeed with cold water but it does react strongly with steam to give magnesium oxide and a gas. Write the word equation for the reaction between magnesium and steam.

MEDIUM

Upper Secondary-IGCSE

IMPORTANT

Cambridge IGCSE Chemistry Workbook 4th Edition>Chapter 8 - Patterns and Properties of Metals>Exercise 8.2>Q b

Choose one metal from the reactivity series that will not react with steam.

MEDIUM

Upper Secondary-IGCSE

IMPORTANT

Cambridge IGCSE Chemistry Workbook 4th Edition>Chapter 8 - Patterns and Properties of Metals>Exercise 8.2>Q c

Choose one metal from the reactivity series that will safely react with dilute sulphuric acid.

HARD

Upper Secondary-IGCSE

IMPORTANT

Cambridge IGCSE Chemistry Workbook 4th Edition>Chapter 8 - Patterns and Properties of Metals>Exercise 8.2>Q d

In each of the experiments below, a piece of metal is placed in a solution of a metal salt. Complete the table of observations.


At start	Colour of metal	grey	_____	silver-coloured	silver-coloured	_____
At start	Colour of solution	colourless	_____	blue	blue	colourless
At finish	Colour of metal	coated with silver coloured crystals	_____	coated with brown solid	silver-coloured	coated with silver-coloured crystals
At finish	Colour of solution	colourless	_____	colourless	blue	_____

Important Questions on Patterns and Properties of Metals

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