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In a Nutshell
| NCERT Point | Simple Meaning |
|---|---|
| Malleability — Metals can be beaten into thin sheets (e.g., aluminium foil). Non-metals like coal and sulphur break when hammered. | Metals flatten; non-metals shatter |
| Ductility — Metals can be drawn into thin wires (e.g., copper wire). Non-metals cannot be made into wires. | Metals stretch into wires; non-metals cannot |
| Sonority — Metals produce a ringing sound when struck (e.g., school bell). Non-metals produce dull sounds. | Metals ring; non-metals thud |
| Lustre — Metals are generally shiny (e.g., gold, silver). Non-metals are generally dull (e.g., coal, sulphur). | Metals shine; non-metals are dull |
| Heat conduction — Metals are good conductors of heat. Non-metals are poor conductors (insulators). | Metals transfer heat fast; non-metals do not |
| Electrical conduction — Metals conduct electricity (e.g., copper wire). Non-metals generally do not. | Metals carry current; non-metals block it |
| Rusting of Iron — Iron reacts with both oxygen (from air) and water to form rust (hydrated iron oxide — reddish-brown). | Iron + air + water → rust |
| Conditions for rusting — Both air and water are necessary. Iron kept in dry air or completely submerged in water does NOT rust. | Either air or water alone cannot cause rusting |
| Prevention of rusting — Painting, oiling, greasing, galvanisation (zinc coating), and alloying prevent rusting. | Coatings block air and water from reaching iron |
| Reaction of metals with oxygen — Metals react with oxygen to form metal oxides, which are basic (e.g., magnesium burns to form MgO — white ash; turns red litmus blue). | Metal oxides are basic in nature |
| Reaction of non-metals with oxygen — Non-metals react with oxygen to form non-metal oxides, which are acidic (e.g., sulphur burns to form SO₂ — sulphur dioxide; turns blue litmus red). | Non-metal oxides are acidic in nature |
| Sodium and potassium are so reactive that they catch fire in air and react violently with water. They are stored under kerosene. | Na and K stored in kerosene to prevent reaction |
| Phosphorus is a very reactive non-metal — it catches fire in air. It is stored under water. | Phosphorus stored under water |
| Exception — Graphite : Graphite is a non-metal (form of carbon) that conducts electricity. Used in electrodes and pencil leads. | Graphite = non-metal that conducts electricity |
| Exception — Iodine : Iodine is a non-metal that has a shiny (lustrous) appearance but does NOT conduct electricity. | Iodine = non-metal that looks shiny |
Quick Revision Table
| Term | Simple Meaning |
|---|---|
| Malleability | Can be hammered flat |
| Ductility | Can be drawn wires |
| Sonority | Makes ringing sound |
| Conductor | Allows heat electricity pass |
| Rusting | Iron turns brown |
| Corrosion | Metal surface deteriorates |
| Galvanisation | Zinc coating prevents rust |
| Brittle | Breaks into pieces |
