Science Class IX: Metals and Non-Metals

Questions and Answers

Which of the following statements about non-metals and metals is true?

Non-metals produce basic oxides in water.

Metals typically produce basic oxides when dissolved in water. (correct)

Non-metals do not react with oxygen.

Most metals produce acidic oxides when dissolved in water.

Which metal is known to be a liquid at room temperature?

Mercury (correct)

Magnesium

Iron

Lead

What is the main characteristic of a metal that is described as malleable?

It is a poor conductor of heat.

It can be hammered or pressed into shapes without breaking. (correct)

It has a high density.

It can be easily stretched into wires.

When metals are burned in air, which of the following products is typically formed?

Oxides Signup and view all the answers

What flame color is typically seen when magnesium burns in air?

White Signup and view all the answers

Which of the following transformations correctly describes a chemical property of metals?

Metals can easily form compounds with non-metals. Signup and view all the answers

Which of the following properties does not apply to metals?

Brittle at room temperature Signup and view all the answers

How do the products formed when metals are burned in air typically behave in water?

They are insoluble in water. Signup and view all the answers

Which metal reacts violently with cold water and causes the evolved hydrogen to catch fire?

Potassium Signup and view all the answers

Which metal is known to float when it reacts with water?

Calcium Signup and view all the answers

What is produced when a metal reacts with water?

Metal oxide and hydrogen gas Signup and view all the answers

Which of the following metals does NOT react with cold water?

Magnesium Signup and view all the answers

Which metal's reaction with water is less violent, but still produces hydrogen?

Calcium Signup and view all the answers

What happens to magnesium when it is placed in hot water?

It reacts to form magnesium hydroxide Signup and view all the answers

Which metals do not react even with steam?

Copper and Gold Signup and view all the answers

In what order should metals be arranged according to their reactivity with water?

Potassium, Sodium, Calcium, Magnesium Signup and view all the answers

What is the role of the anode in electrolytic refining?

It dissolves into the electrolyte. Signup and view all the answers

In the process of electrolytic refining, what happens to the soluble impurities?

They remain in the electrolyte solution. Signup and view all the answers

Which electrolyte is used during the electrolytic refining of copper?

Acidified copper sulphate solution. Signup and view all the answers

What is anode mud?

Insoluble impurities that settle at the bottom of the anode. Signup and view all the answers

Which of the following metals undergoes corrosion by reacting with sulphur in the air?

Silver. Signup and view all the answers

During the refining process, what happens to the pure metal at the cathode?

It is deposited from the electrolyte. Signup and view all the answers

What happens to copper when it reacts with moist carbon dioxide in the air?

It gains a green coat. Signup and view all the answers

Which of the following is true about the cathode in electrolytic refining?

It is a thin strip of pure metal. Signup and view all the answers

What is the composition of an alloy that is described as 22 parts of pure gold?

22 parts gold and 2 parts silver or copper Signup and view all the answers

Why are brass and bronze not considered good conductors of electricity?

Their electrical conductivity is less than that of pure metals. Signup and view all the answers

What is the primary use for solder, an alloy of lead and tin?

Welding electrical wires together Signup and view all the answers

What is defined as an amalgam in metallurgy?

An alloy containing mercury Signup and view all the answers

What process did ancient Indian iron workers develop to prevent rusting?

An unknown rust-resistant process Signup and view all the answers

What is the height of the iron pillar near the Qutub Minar in Delhi?

8 meters Signup and view all the answers

What weight does the iron pillar near the Qutub Minar approximately have?

6000 kg Signup and view all the answers

Which elements are combined to create brass?

Copper and zinc Signup and view all the answers

What is the term used to describe the shining surface of metals in their pure state?

Metallic lustre Signup and view all the answers

Which of the following metals is known to be soft and can be easily cut with a knife?

Sodium Signup and view all the answers

What is the primary method used to group substances based on their properties?

Physical properties Signup and view all the answers

Why is it necessary to handle sodium metal with care?

It is highly reactive Signup and view all the answers

What is the purpose of rubbing metal samples with sandpaper in Activity 3.1?

To clean the surface of the metal Signup and view all the answers

Which of the following metals is known to be hard and difficult to cut with a knife?

All of the above Signup and view all the answers

What is the purpose of striking a metal with a hammer in Activity 3.3?

To test its hardness Signup and view all the answers

What is the term used to describe the ability of a metal to be shaped or molded without breaking?

Malleability Signup and view all the answers

Study Notes

Classification of Elements

Elements are classified into metals and non-metals based on their physical and chemical properties.
Understanding these classifications helps in identifying everyday uses of metals and non-metals.

Physical Properties of Metals

Metals exhibit a shiny appearance known as metallic lustre when in pure form.
They are generally hard, with varying degrees of hardness.
Metals can be molded or shaped; they are described as malleable (can be hammered into sheets) and ductile (can be drawn into wires).

Reactivity of Metals

Metals react with water, producing a metal oxide and hydrogen gas.
Reactivity varies: for example, potassium and sodium react violently with cold water, producing heat and igniting hydrogen.
Calcium reacts less violently with water, while magnesium does not react with cold water but does with hot water.

Electrolytic Refining

Metals such as copper and zinc can be refined using electrolytic refining.
Impure metal acts as the anode, while a pure metal strip acts as the cathode in an electrolyte solution.
During the process, the pure metal from the anode dissolves and deposits on the cathode.

Corrosion

Corrosion is the deterioration of metal due to chemical reactions, such as silver reacting with sulfide in the air or copper reacting with carbon dioxide.
Alloys, such as brass (copper and zinc) and bronze (copper and tin), exhibit different physical properties than their constituent metals.

Historical Metallurgy Example

The Iron Pillar of Delhi, created over 1600 years ago, showcases advanced ancient Indian metallurgy techniques that prevented rusting.
This pillar is notable for its height (8 m) and weight (6000 kg), and it remains rust-resistant, drawing attention from scientists globally.

Key Collaborative Questions and Definitions

Explore specific metals (liquid at room temperature, best conductor of heat, etc.) and their traits.
Definitions:
- Mineral: A naturally occurring solid substance.
- Ore: A naturally occurring solid material from which a metal can be extracted profitably.
- Gangue: The worthless material surrounding an ore.
Recognize that some metals occur naturally in the free state, while others need extraction processes to be obtained from their ores.

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Description

This quiz covers Chapter 3 on Metals and Non-Metals from Class IX Science. Explore the properties, classifications, and everyday uses of these elements. Test your understanding of how these properties relate to their applications in daily life.