Materials : Metals and Non-metals | Chapter Assessment | English | Grade 8

Which of the following is not a metal?

• Iron

• Aluminium

• Copper

• Plastic

Answer explanation

Iron, Aluminium and Copper are metals, whereas plastic is not a metal.

Which of the following is not a property of metals?

• Malleable

• Bad Conductors of heat

• Good Conductors of Electricity

• Ductile

Answer explanation

Metals are malleable, ductile and good conductors of heat and electricity.

Which of the following is the only metal found in liquid state at room temperature?

• Sodium

• Mercury

• Potassium

• Copper

Answer explanation

Mercury is the only known metal that is found in liquid state at room temperature.

Rusting of iron takes place because of the presence of which gas?

• Nitrogen dioxide

• Carbon Dioxide

• Oxygen

• Nitrogen

Answer explanation

Rust is actually a chemical compound called iron oxide that is formed when iron reacts with oxygen and water present in air.

Magnesium on reacting with oxygen gives __________ .

• Magnesium Dioxide

• Magnesium Hydroxide

• Magnesium Peroxide

• Magnesium trioxide

Answer explanation

Magnesium on reacting with oxygen give MgO, which is called magnesium peroxide.

Which of the following non-metal, when exposed to gases present in the atmosphere, catches fire?

• Sulphur

• Carbon

• Selenium

• Phosphorus

Answer explanation

Phosphorus is a highly unstable non-metal. It catches fire when exposed to air. This is the reason it is stored in water.

Metals on reacting with acids produce _____ gas.

• Hydrogen

• Oxygen

• Carbon Dioxide

• Nitrogen

Answer explanation

Metals react with acids and produce hydrogen gas that burns with a 'pop' sound when a burning match stick is brought near the mouth of the test tube.

Zinc Sulphate + Copper →

• Copper Sulphate + Zinc

• Copper + Zinc + Sulphur Dioxide

• Copper + Zinc + Sulphur + Oxygen

• Does not react

Answer explanation

Copper is a less reactive metal than zinc, therefore it cannot replace zinc in zinc sulphate.