Introduction

Everything around us is made of different types of materials. Some have a lustrous (shiny surface), are good conductors of heat and electricity, and are malleable (can be beaten into sheets) and ductile (can be drawn into wires), like iron and copper. Others have a dull appearance, are brittle (break easily), and are poor conductors (except graphite). These materials are classified into two main categories: metals and non-metals.

In this chapter, we will explore their properties, reactions, and uses in daily life.

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1. What Are Metals?
Metals are substances that have certain unique characteristics, such as shine, hardness, and the ability to conduct heat and electricity.

Examples of Metals:

Common Metals: Iron, copper, aluminum
Precious Metals: Gold, silver, platinum
Industrial Metals: Zinc, lead, magnesium

Properties of Metals:

Lustrous (Shiny Surface) – Metals like gold and silver shine when polished.
Good Conductors of Electricity – Copper and aluminum wires are used in electrical wiring.
Malleable (Can Be Beaten into Sheets) – Aluminum foil and gold sheets are examples.
Ductile (Can Be Drawn into Wires) – Copper and iron wires are commonly used.
Hard and Strong – Metals like iron and steel are used in construction.
High Melting and Boiling Points – Most metals can withstand high temperatures.
Sonorous (Produce Sound When Hit) – Bells are made of metal because they produce a ringing sound.

2. What Are Non-Metals?
Non-metals are substances that lack metallic properties. They are often soft, brittle, and poor conductors of heat and electricity.

Examples of Non-Metals:

Common Non-Metals: Carbon, sulfur, phosphorus
Gaseous Non-Metals: Oxygen, nitrogen, hydrogen
Non-Metal Used in Industry: Chlorine (used in water purification)

Properties of Non-Metals:

Dull Appearance – They do not have a shiny surface (except iodine).
Poor Conductors of Electricity – Graphite (carbon) is an exception.
Brittle (Breaks Easily) – Sulfur and phosphorus break when pressed.
Low Melting and Boiling Points – Most non-metals have low melting points.
Non-Sonorous – They do not produce sound when struck.
Non-Malleable and Non-Ductile – They cannot be beaten into sheets or drawn into wires.

3. Chemical Properties of Metals and Non-Metals

(i) Reaction with Oxygen

Metals + Oxygen → Metal Oxide
Example: Iron reacts with oxygen and water to form rust (Rusting: Iron + Oxygen + Water → Rust).
Most metal oxides are basic and turn red litmus blue.

Non-Metals + Oxygen → Non-Metal Oxide
Example: Carbon burns in oxygen to form carbon dioxide.
Non-metal oxides are acidic and turn blue litmus red.

(ii) Reaction with Water

Metals + Water → Metal Hydroxide + Hydrogen Gas
Example: Sodium reacts violently with water.
Some metals like iron react slowly, while gold does not react.

Non-Metals + Water
Most non-metals do not react with water.

(iii) Reaction with Acids

Metals + Acid → Salt + Hydrogen Gas
Example: Zinc reacts with hydrochloric acid to produce zinc chloride and hydrogen gas.

Non-Metals + Acid
Non-metals do not react with acids because they do not release electrons.

(iv) Reaction with Bases

Metals react with strong bases to produce hydrogen gas.
Non-metals generally do not react with bases.

4. Uses of Metals and Non-Metals

Uses of Metals:

Construction: Iron and steel are used in buildings, bridges, and machines.
Electricity: Copper and aluminum are used in electrical wiring.
Jewelry: Gold, silver, and platinum are used in ornaments.
Cooking Utensils: Aluminum and stainless steel are used in cookware.
Transportation: Vehicles, airplanes, and ships are made using metals.

Uses of Non-Metals:

Breathing: Oxygen is essential for life.
Fertilizers: Nitrogen, phosphorus, and potassium help plants grow.
Medicine: Iodine is used for treating wounds.
Water Purification: Chlorine kills germs in water.
Fuel: Coal and natural gas are used for energy.

5. Alloys – Mixing Metals for Strength

Examples of Alloys:

Steel = Iron + Carbon (Stronger than pure iron)
Brass = Copper + Zinc (Used in musical instruments)
Bronze = Copper + Tin (Used for statues and medals)
Stainless Steel = Iron + Chromium + Nickel (Used in kitchenware)

6. Corrosion – When Metals Get Damaged
Metals react with air, water, and other substances, leading to corrosion.

Examples of Corrosion:

Rusting of Iron – Forms brownish-red rust.
Greenish Coating on Copper – Forms due to moisture reaction.
Black Coating on Silver – Due to reaction with sulfur compounds.

How to Prevent Corrosion?

Painting – Prevents contact with air and moisture.
Oiling and Greasing – Forms a protective layer.
Galvanization – Coating iron with zinc.
Electroplating – Coating metal with another metal.