Metals and Non-metals

Notes on Metals and Non-Metals

Classification of Elements

Elements are primarily classified into metals and non-metals based on their physical and chemical properties. Understanding these properties is essential to appreciate the roles these elements play in daily life and various industries.

Physical Properties of Metals

1. Lustrous Surface: Metals possess a shining appearance known as metallic lustre. When cleaned, metals like iron, aluminum, and magnesium exhibit this shiny surface.

2. Hardness: Most metals are hard and can vary in hardness across different types. Metals such as iron and aluminum can withstand significant force.

3. Malleability: Metals can be hammered into thin sheets without breaking. Gold and silver are particularly known for their high malleability.

4. Ductility: This refers to the ability of metals to be drawn into wires. Gold is notably the most ductile, as a small amount can yield long wires.

5. Conductivity: Metals are excellent conductors of heat and electricity. The chapter explains that this property allows for their use in wiring and cooking vessels, as they quickly transfer heat and energy.

6. Sonority: Upon striking, metals produce a ringing sound, making them sonorous. This is why bells are typically made from metals.

Physical Properties of Non-Metals

Contrastingly, non-metals exhibit properties opposite to metals:

1. State: Non-metals can exist as solids (like carbon and sulphur), liquids (like bromine), or gases (like oxygen) at room temperature.
2. Brittleness: Unlike metals, if non-metals like sulfur are subjected to force, they tend to break rather than deform.
3. Poor Conductors: Non-metals generally do not conduct heat or electricity well, with graphite being a notable exception.

Chemical Properties

The reactivity and chemical behaviors of metals and non-metals differ greatly:

1. Oxides Formation: Metals typically form basic oxides when they react with oxygen, while non-metals yield acidic oxides. For example, magnesium forms magnesium oxide, which is basic, while sulfur forms sulfur dioxide, which is acidic.

2. Reactivity with Water and Acids: Metals like sodium and potassium react readily with water, producing hydroxides and hydrogen gas. Higher up on the reactivity series, metals like magnesium react with hot water or steam. Non-metals do not displace hydrogen from acids.

3. Displacement Reactions: More reactive metals can displace less reactive metals in solution. For instance, zinc can replace copper in copper sulfate solution.

Reactivity Series

This section outlines a list of metals ordered from most reactive to least reactive, with potassium being the most reactive and gold being among the least. This series helps predict how metals will behave in different reactions.

Extraction of Metals

The chapter discusses the metallurgy process, which involves:

1. Extraction from Ores: Metals are extracted from ores by methods depending on their reactivity. Less reactive metals can be obtained by simple heating, while more reactive metals require electrolysis.
2. Enrichment: This step involves removing impurities from ores to enhance the concentration of metal.
3. Refining: After extraction, metals are often impure and need refining (pure form) through various methods, including electrolytic refining.

Corrosion and Its Prevention

Corrosion significantly affects metals like iron, leading to rust. Key prevention techniques include:

• Coating with grease or paint
• Galvanization (coating with zinc)
• Alloying to improve resistance (e.g., stainless steel). The section also mentions that the ancient iron pillar in Delhi is an example of successful anti-corrosion practices.

Summary of Important Concepts

• Metals Characteristics: Lustrous, malleable, ductile, good conductors of heat and electricity.
• Non-Metals Characteristics: Generally brittle, poor conductors, can exist in various states.
• Reactivity: Metals can displace less reactive metals; different reactions occur when they interact with water, acids, and oxygen.
• Extraction Methods: Vary based on the metal's position in the reactivity series; refining methods are necessary for purity.
• Corrosion Prevention: Implemented through various methods to extend the life of metals.

These notes encapsulate the key physical and chemical properties of metals and non-metals, along with their interactive behaviors and practical applications in everyday life.

1. Classification of elements into metals and non-metals is based on physical and chemical properties.
2. Metals are lustrous, malleable, ductile, and good conductors of heat and electricity.
3. Non-metals are generally brittle, poor conductors, and can exist as solids, liquids, or gases.
4. Metals generally form basic oxides while non-metals form acidic oxides.
5. The reactivity series ranks metals from most to least reactive, affecting displacement reactions.
6. Metals are extracted from their ores through reduction and electrolysis, requiring different methods.
7. Corrosion leads to rusting; prevention methods include galvanizing and alloying.
8. Understanding properties aids in the practical application of metals and non-metals in daily life.