Questions
5 questions on average
Difficulty
Medium
Importance
Core — never skip
Overview
Metals and Non-metals is a foundational unit in chemistry that explains the elemental behavior, chemical reactivity, and industrial extraction processes. Mastering this topic is essential as it forms the basis for understanding metallurgy, periodic trends, and corrosion prevention methods frequently tested in competitive board and PSU exams.
The Reactivity Series of Metals
The reactivity series is a list of metals arranged in descending order of their chemical reactivity. Understanding this sequence allows aspirants to predict displacement reactions and identify which metals can displace others from their salt solutions.
- Potassium (K) is the most reactive metal
- Gold (Au) and Platinum (Pt) are the least reactive
- Metals above Hydrogen displace it from acids
- Displacement logic: More reactive metal displaces less reactive metal from its salt solution
- MNEMONIC: K, Na, Ca, Mg, Al, Zn, Fe, Pb, H, Cu, Hg, Ag, Au
Extraction of Metals (Metallurgy)
Metallurgy involves the separation of metals from their ores through distinct physical and chemical processes depending on their reactivity. This section focuses on concentration, isolation, and refining phases.
- Roasting: Heating sulphide ores in excess air
- Calcination: Heating carbonate ores in limited air
- Electrolytic Refining: Used for purifying metals like Copper
- Thermite Process: Fe2O3 + 2Al -> 2Fe + Al2O3
- Highly reactive metals extracted via electrolysis of molten salts
Corrosion and Prevention
Corrosion is the gradual deterioration of metals due to chemical reactions with the atmosphere. Protecting metals from oxidation is a key application-based topic frequently asked in exams.
- Rusting of iron formula: 4Fe + 3O2 + 2xH2O -> 2Fe2O3.xH2O
- Galvanization: Coating iron with a thin layer of Zinc
- Alloying: Adding non-metals or metals to enhance properties
- Anodizing: Thickening the oxide layer on Aluminum
- Brass: Alloy of Copper and Zinc
Formula Sheet
Fe2O3.xH2O (Rust)
2Fe + 3/2O2 + xH2O -> Fe2O3.xH2O
2Al + Fe2O3 -> Al2O3 + 2Fe (Thermite reaction)
Exam Tip
Always balance chemical equations in metallurgical processes, as examiners award full marks for the stoichiometry and states of reactants.
Common Mistakes
- Confusing Roasting (sulfide ores) with Calcination (carbonate ores) during exams.
- Forgetting the presence of water in the chemical formula for rust.
- Misremembering the order of metals in the reactivity series specifically around the Hydrogen boundary.
More Revision Notes
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