METALS & NON-METALS — CORE CONCEPT Metals and Non-Metals are two broad categories of elements. Understanding their properties and reactions is essential for RRB Group D Science.
--- CORE CONCEPT
Metals are elements that are shiny, conduct electricity and heat, and can be beaten into sheets or drawn into wires. Non-Metals are elements that are generally dull, poor conductors, and brittle in solid form. About 80% of all elements in the periodic table are metals. Non-metals are found on the right side of the periodic table.
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METALS: - Lustrous (shiny surface) - Hard and strong (except Na and K which are soft) - Good conductors of heat and electricity - Malleable — can be hammered into thin sheets (Gold is most malleable) - Ductile — can be drawn into wires (Gold is most ductile; Silver is best conductor) - High melting and boiling points (except Mercury — liquid at room temp; Gallium — melts in hand) - Produce metallic sound when struck (Sonorous) - Generally solid at room temperature (except Mercury) NON-METALS: - Non-lustrous (except Iodine and Diamond which are shiny) - Poor conductors (except Graphite which conducts electricity) - Brittle in solid form — cannot be hammered - Low melting and boiling points (except Diamond — highest melting point) - Non-sonorous - Can be solid, liquid (Bromine), or gas at room temperature --- CHEMICAL REACTIONS OF METALS With Oxygen: Metal + Oxygen → Metal Oxide (Basic in nature) Example: 4Na + O2 → 2Na2O With Water: - Na and K react violently with cold water - Mg reacts with hot water - Fe reacts with steam only - Cu, Au, Ag — do NOT react with water With Acids: Metal + Dilute Acid → Salt + Hydrogen gas Example: Zn + H2SO4 → ZnSO4 + H2 Non-metals form acidic oxides (e.g., SO2, CO2 dissolve in water to form acids). --- REACTIVITY SERIES (Important Order to Remember) K > Na > Ca > Mg > Al > Zn > Fe > Ni > Sn > Pb > H > Cu > Hg > Ag > Au Trick: King Narendra Can Make A Zinc Fence Now Since Police Have Caught Him Smoking Alcohol ---
RRB Group D frequently asks: - Which metal is liquid at room temperature? (Mercury) - Which non-metal conducts electricity? (Graphite) - Which metal is most malleable? (Gold) - Which gas is produced when metal reacts with acid? (Hydrogen) - Best conductor of electricity among metals? (Silver) --- SHORTCUT / TRICK Trick 1 — Exceptions to remember (these are the MCQ traps): - Mercury = metal + liquid at room temp - Bromine = non-metal + liquid at room temp - Graphite = non-metal + conducts electricity - Iodine = non-metal + shiny/lustrous - Sodium & Potassium = metals + very soft, stored in kerosene - Diamond = non-metal + hardest natural substance + highest melting point Trick 2 — Acid reaction memory: 'Metals above Hydrogen in reactivity series can displace H2 from dilute acids.' Copper, Silver, Gold CANNOT. ---
Identify the type of reaction — Metal + Water (Steam)
Iron reacts with steam (not cold or hot water)
Write the equation: 3Fe + 4H2O (steam) → Fe3O4 + 4H2
Product is Iron (II,III) Oxide — Fe3O4 (black magnetic oxide) and Hydrogen gas. Answer: Fe3O4 and Hydrogen gas (H2) ---
Students confuse 'best conductor' with 'most malleable.' Silver is the BEST conductor of electricity. Gold is the MOST malleable and ductile. Do NOT mix these two up — this is a very common MCQ trap in RRB exams.
8graded MCQs · easy to hard · full solution & trap analysis