This lesson explains the physical and chemical properties of metals and non-metals, the reactivity series, extraction of metals from ores, and important metallurgical processes.

1. Core Concepts (Short Notes)

23.1 Metals

Metals are elements that generally:

• Are shiny (lustrous)

• Are good conductors of heat & electricity

• Are malleable (can be hammered)

• Are ductile (can be drawn into wires)

• Have high density and melting points

23.2 Non-Metals

Non-metals:

• Are poor conductors

• Are brittle (if solid)

• Often have low melting & boiling points

• Exist as solids, liquids, or gases

• Form acidic oxides

23.3 Metalloids

Elements with intermediate properties (e.g., Si, Ge).

2. Chemical Properties

23.4 Metal Reactivity

Most metals react with:

• Oxygen: forming metal oxides (basic)

• Water: forming hydroxides + hydrogen (only reactive metals)

• Acids: forming salts + hydrogen

• Halogens: forming metal halides

23.5 Non-Metal Reactivity

• React with oxygen → acidic oxides

• Often gain electrons to form anions

• Form covalent compounds

3. Reactivity Series

A list of metals arranged by decreasing reactivity:

Uses:

• Predict displacement reactions

• Determine extraction method

• Identify whether a metal reacts with water/acid

Example (displacement): Zn + CuSO₄ → ZnSO₄ + Cu

4. Metallurgy (Extraction of Metals)

23.6 Stages of Metallurgy

1. Concentration of ore – removing impurities

2. Extraction – using chemical or electrochemical methods

3. Refining – purifying the metal

23.7 Extraction Based on Reactivity

• Highly reactive metals (K, Na, Ca, Mg, Al): extracted by electrolysis of molten salts.

• Moderate reactive metals (Zn, Fe, Pb): extracted by reduction using carbon/coke.

• Low reactive metals (Cu, Ag, Au): found free or extracted by roasting or smelting.

23.8 Blast Furnace (Iron Extraction)

Ore: Hematite (Fe₂O₃)

Key reactions:

• C + O₂ → CO₂

• CO₂ + C → 2CO

• Fe₂O₃ + 3CO → 2Fe + 3CO₂

Products:

• Pig iron → converted to steel

23.9 Electrolysis of Aluminium (Hall–Héroult Process)

• Ore: Bauxite (Al₂O₃)

• Dissolved in molten cryolite

• Al³⁺ ions reduced at cathode → aluminium metal

5. Alloying

23.10 What Are Alloys?

Mixtures of metals (sometimes with non-metals) to improve properties.

Examples:

• Brass: Cu + Zn

• Bronze: Cu + Sn

• Stainless steel: Fe + Cr + Ni

Alloys improve strength, corrosion resistance, hardness, and conductivity.

6. Tips & Tricks for Exams

• Remember the reactivity series—many questions rely on it.

• Metals above hydrogen react with acids; below do not.

• Strong reducing agents are found at the top of the series.

• Blast furnace questions often appear with diagrams.

• Know the difference between roasting, calcination, and smelting.

• Aluminium extraction is always via electrolysis.

7. Important Points to Remember

• Metals lose electrons; non-metals gain electrons.

• Metal oxides are basic; non-metal oxides are acidic.

• Reactivity determines extraction method.

• Alloys are engineered for better performance.

Iron metallurgy is economically crucial worldwide.