Metals and Non-metals

An element X forms two oxides XO and XO₂. Oxide XO is neutral whereas XO₂ is acidic in nature. Identify element X. Would you call it a metal or non-metal? [CBSE 2025]

What is meant by: (a) Roasting (b) Calcination? Give one example of each. [CBSE 2024]

Write equations for the reactions of: (a) Iron with steam (b) Calcium with water (c) Potassium with water [CBSE 2023]

What is an alloy? Give two examples with their composition and uses. [CBSE 2022]

Why is sodium kept immersed in kerosene oil? What happens when: (a) Sodium metal is dropped in water? (b) Sodium reacts with oxygen? [CBSE 2021]

• Malleable and ductile
• Good conductors of heat and electricity
• Lustrous (shiny)
• High melting and boiling points
• Form basic oxides
• Lose electrons (electropositive)

• Brittle (if solid)
• Poor conductors (insulators)
• Not lustrous (dull)
• Low melting and boiling points
• Form acidic oxides
• Gain electrons (electronegative)

Most reactive: K, Na, Ca, Mg, Al, Zn, Fe, Pb, H, Cu, Hg, Ag, Au, Pt :Least reactive

More reactive metal displaces less reactive metal from its salt solution

Brass: Cu + Zn (75:25) Bronze: Cu + Sn (90:10) Steel: Fe + C (98:2) Stainless steel: Fe + Cr + Ni Solder: Pb + Sn (50:50)

Steps in metallurgy:

1. Enrichment/Concentration of ore
2. Conversion to oxide (Roasting/Calcination)
3. Reduction to metal
4. Refining/Purification

Roasting: Heating ore in presence of air 2ZnS + 3O₂ → 2ZnO + 2SO₂

Calcination: Heating ore in absence of air ZnCO₃ → ZnO + CO₂

Highly exothermic reaction: Fe₂O₃ + 2Al → 2Fe + Al₂O₃ + Heat

Uses: Welding railway tracks Aluminum is more reactive than iron, so it reduces iron oxide

Corrosion: Slow eating away of metal by air/water Rust: Fe₂O₃.xH₂O (hydrated iron oxide)

Prevention methods:

• Painting/Greasing
• Galvanization (coating with zinc)
• Electroplating
• Alloying