Exercise 5.1 & 5.2 Metals and non-metals [Should Do]

Match the following five non-metals to their uses.

• matches

• chlorine

• keeping swimming pool water clean

• carbon

• portable water purifying kits

• iodine

• barbecue charcoal

• phosphorus

• car tyres

• sulphur

All metals are magnetic. True or false?

• True

• False

Solid non-metals are brittle. True or false?

• True

• False

All metals are solids. True or false?

• True

• False

Answer explanation

Mercury is a metal. However it exits as liquid at room temperature.

All non-metals look dull. True or false?

• True

• False

Answer explanation

Iodine is a non-metal but it is shiny.

This is a shiny liquid. The melting point is -39 ⁰C and the boiling point is 357 ^oC. It conduct electricity. It is a ​ (a)   . It is toxic. It has been used in thermometer. It is​ (b)  

• metal
• mercury
• non-metal
• copper
• carbon
• sodium

This is a transparent gas with a melting point of -219 ^oC and a boiling point of -183 ^oC. It does not conduct electricity and hence it is a ​ (a)   . It is essential for respiration in most living things and in burning. It is ​ (b)   .

• non-metal
• oxygen
• metal
• helium
• nitrogen
• carbon dioxide

This is an unreactive gas with a melting point of -272 ^oC and a boiling point of -269 ^oC. It does not conduct electricity and so it is a ​ (a)   . It is very light. It is used in airships and inflate balloons. It is ​ (b)  

• non-metal
• helium
• metal
• nitrogen
• hydrogen

This is a reddish shiny solid. It conducts heat and electricity well. It has a melting point of 1082 ^oC and a boiling point of 2580 ^oC.

• It is silver

• It is copper

• It is used for electrical wiring

• It is used for cooking pans

This is a yellow, brittle solid that does not conduct electricity. The melting point is 119 ^oC and the boiling point is 445 ^oC. It is used to harden rubber.

• It is a metal

• It is iodine

• It is sulphur

• It is a non-metal