Metals and Non-metals — Class 10 Science Notes & Important Questions | MP Board

Chapter Overview

The chapter Metals and Non-metals is a foundational topic in the MP Board Class 10 Science syllabus that explores the physical and chemical behavior of elements around us. Students learn how metals and non-metals differ in their properties, how they react with air, water, and acids, and how ionic bonds are formed between them. Additionally, the chapter covers crucial industrial processes including the extraction of metals from their ores and methods to prevent corrosion.

Why Important for Board Exam

In the annual High School examination conducted by the MP Board, the chapter on Metals and Non-metals carries significant weightage, usually accounting for 5 to 7 marks. Questions from this chapter range from objective-type questions (MCQs, fill in the blanks, match the following) to analytical short-answer and long-answer questions. Key concepts like the reactivity series, electrolytic refining, difference between calcination and roasting, and properties of ionic compounds are frequently asked in the examination. Mastering this chapter is essential for securing top marks in the MP Board Class 10 Science paper.

Key Concepts & Topics Covered

• Physical Properties: Comparative study of physical traits such as malleability, ductility, electrical conductivity, sonority, and metallic lustre.
• Chemical Properties of Metals: Reactions with oxygen (formation of basic and amphoteric oxides), water, dilute acids, and salt solutions.
• Reactivity Series: Arrangement of metals in decreasing order of their chemical reactivity.
• Reaction Between Metals and Non-metals: Formation of ionic (electrovalent) bonds through electron transfer and key properties of ionic compounds.
• Occurrence of Metals: Metallurgy steps including concentration of ore, extraction of low, medium, and high reactivity metals, roasting, calcination, and thermite reduction.
• Refining of Metals: Purification techniques, particularly electrolytic refining of copper.
• Corrosion and Prevention: Chemical process of rusting, conditions required for corrosion, and protective techniques like galvanisation, anodising, and alloying.

Important Definitions

To score high marks in short-definition questions, students should revise these key scientific terms using our curated reference guide:

Term	Definition
Malleability	The physical property of a metal that allows it to be beaten into thin sheets without breaking.
Ductility	The property of a metal that enables it to be drawn into thin wires.
Amphoteric Oxide	Metal oxides that react with both acids and bases to produce salt and water (e.g., Aluminum oxide, Zinc oxide).
Reactivity Series	A vertical list of metals arranged in decreasing order of their chemical activity.
Ionic Compound	A compound formed by the transfer of electrons from a metal atom to a non-metal atom, held together by strong electrostatic forces.
Ore	A naturally occurring mineral or rock from which a metal can be extracted conveniently and profitably.
Gangue	Earthy impurities such as soil, sand, and clay associated with ores mined from the earth.
Roasting	The process of heating sulfide ores strongly in the presence of excess air to convert them into metal oxides.
Calcination	The process of heating carbonate ores strongly in limited or restricted air to convert them into metal oxides.
Galvanisation	A method of protecting steel and iron from rusting by applying a thin protective coating of zinc metal.
Alloy	A homogeneous mixture of two or more metals, or a metal and a non-metal, designed to enhance specific properties.

Chapter Summary in Simple Language

1. Physical Properties Comparison

Metals are generally solid at room temperature (except mercury, which is liquid), hard, malleable, ductile, sonorous, and good conductors of heat and electricity. They possess a shiny surface known as metallic lustre. In contrast, non-metals exist in solid, liquid (bromine), or gaseous states. They are non-malleable, brittle, non-ductile, non-sonorous, and poor conductors of heat and electricity. Exceptions must be remembered carefully for the MP Board exam: iodine is a non-metal with lustre, graphite (carbon) conducts electricity, and diamond is the hardest natural substance known.

2. Chemical Properties of Metals

When metals react with chemical agents, they display distinct behaviors:

• Reaction with Air/Oxygen: Metals burn in oxygen to form metal oxides. Most metal oxides are basic in nature, but oxides like aluminum oxide (Al₂O₃) and zinc oxide (ZnO) show both acidic and basic behavior; these are called amphoteric oxides.
  Al₂O₃ + 6HCl → 2AlCl₃ + 3H₂O
  Al₂O₃ + 2NaOH → 2NaAlO₂ + H₂O
• Reaction with Water: Highly reactive metals like sodium and potassium react violently with cold water, releasing hydrogen gas and heat energy. Calcium reacts less violently, while magnesium reacts with hot water. Metals like aluminum, iron, and zinc react only with steam to form metal oxides and hydrogen. Gold, silver, copper, and lead do not react with water at all.
• Reaction with Acids: Metals above hydrogen in the reactivity series react with dilute acids to produce a metal salt and hydrogen gas. Metals do not evolve hydrogen gas when reacting with nitric acid (HNO₃) because it is a strong oxidizing agent.
• Displacement Reactions: A more reactive metal displaces a less reactive metal from its aqueous salt solution. For instance, iron nail placed in blue copper sulfate solution displaces copper, turning the solution light green.

3. Reactivity Series and Ionic Bonding

The reactivity series arranges metals from most reactive (Potassium, Sodium) at the top to least reactive (Gold, Platinum) at the bottom. This series determines how metals bond and react.

When metals react with non-metals, metal atoms lose valence electrons to attain a stable octet, forming positively charged cations. Non-metal atoms gain these valence electrons to form negatively charged anions. The strong electrostatic force of attraction between oppositely charged ions forms an ionic bond. Students preparing MP Board Metals and Non-metals notes should remember that ionic compounds have high melting and boiling points, are soluble in water, and conduct electricity in an aqueous solution or molten state, but not in solid state.

4. Metallurgy: Extraction of Metals

Metals are extracted from their naturally occurring ores through metallurgy, which involves three main steps based on reactivity:

1. Enrichment of Ore: Removing unwanted earthy impurities (gangue) using techniques like hydraulic washing, magnetic separation, or froth flotation.
2. Extracting Metals from Concentrated Ores:
   • Metals of Low Reactivity: Extracted by heating their ores alone (e.g., Cinnabar HgS yields Mercury).
   • Metals of Medium Reactivity (Fe, Zn, Pb): Sulfide ores are converted to oxides via Roasting (heating in excess air), whereas carbonate ores are converted to oxides via Calcination (heating in limited air). The resulting metal oxides are reduced to metals using carbon (coke) or reactive metals like aluminum (Thermite process).
   • Metals of High Reactivity (Na, Mg, Ca, Al): Extracted by electrolytic reduction of their molten chlorides or oxides because carbon cannot reduce highly reactive metal oxides.
3. Refining of Metals: Impure metals are purified by electrolytic refining. In copper refining, impure copper acts as the anode, pure copper strip acts as the cathode, and acidified copper sulfate acts as the electrolyte.

5. Corrosion and Prevention

Corrosion is the slow degradation of metal surfaces caused by chemical reactions with air, moisture, and acids in the environment. Iron forms a reddish-brown flaky substance called rust (Fe₂O₃·xH₂O). Copper forms a green coating of basic copper carbonate, and silver turns black due to silver sulfide formation.

Methods of prevention include painting, greasing, galvanisation (coating with zinc), chrome plating, anodising, and preparing alloys like stainless steel (iron, chromium, nickel) or brass (copper and zinc).

Frequently Asked Questions

Q1. What are amphoteric oxides? Give two examples along with balanced chemical equations.

Answer: Amphoteric oxides are metal oxides that react with both acids and bases to produce salt and water, exhibiting both acidic and basic character. The two classic examples are Aluminum oxide (Al₂O₃) and Zinc oxide (ZnO).

Equation with acid: Al₂O₃ + 6HCl → 2AlCl₃ + 3H₂O
Equation with base: Al₂O₃ + 2NaOH → 2NaAlO₂ (Sodium aluminate) + H₂O

Q2. Differentiate between Roasting and Calcination with clear points.

Answer: Roasting and Calcination are two thermal processes used in metallurgy:

• Roasting: Used for sulfide ores; ore is heated strongly in the presence of excess air; produces sulfur dioxide gas. (e.g., 2ZnS + 3O₂ → 2ZnO + 2SO₂)
• Calcination: Used for carbonate ores; ore is heated strongly in limited or no air; produces carbon dioxide gas. (e.g., ZnCO₃ → ZnO + CO₂)

Q3. Why do ionic compounds have high melting points and conduct electricity only in liquid state?

Answer: Ionic compounds consist of positively and negatively charged ions held together by extremely strong electrostatic forces of attraction. A large amount of heat energy is required to break these strong inter-ionic bonds, resulting in high melting points. In solid state, ions are locked in fixed lattice positions and cannot move. However, in molten or dissolved state, electrostatic forces weaken, allowing free movement of ions to conduct electricity.

Q4. Which metal does not react with dilute hydrochloric acid and why?

Answer: Copper, silver, and gold do not react with dilute hydrochloric acid. This is because these metals lie below hydrogen in the reactivity series and are unable to displace hydrogen ions (H⁺) from dilute acids.

Tips to Score Full Marks

• Memorize Reactivity Mnemonics: Memorize the reactivity series in correct order so you can easily answer displacement reactions and metallurgy questions.
• Practice Balanced Chemical Equations: Always write complete chemical equations for reactions involving air, water, amphoteric oxides, roasting, and calcination. Unbalanced equations lead to mark deductions in MP Board valuation.
• Draw Clear Diagrams: Practice labeling diagrams such as Electrolytic Refining of Copper, Testing Electrical Conductivity, and Action of Steam on a Metal. Neat labeled diagrams boost your presentation score significantly.
• Focus on Exceptional Cases: Pay close attention to exceptions (e.g., iodine is lustrous, graphite conducts electricity, mercury is liquid). Objective questions in MP Board Class 10 Science often target these unique points.
• Solve Previous Years Question Papers: Regularly solve MP Board Class 10 Science important questions from past 5 years to understand board pattern trends and time management.