CBSE Class 10 Science: Metals & Non-Metals — Notes 2026

Physical Properties of Metals

• Lustrous, malleable, ductile, good conductors of heat and electricity, high melting points (except Na, K, Hg, Ga)
• Hardest metal: chromium; lightest metal: lithium; best conductor: silver; most ductile: gold
• Exceptions: mercury (liquid), sodium (soft), tungsten (high mp 3422°C)

Physical Properties of Non-Metals

• Generally dull, brittle (in solid state), poor conductors; lower melting points than metals
• Exceptions: graphite (conducts electricity), diamond (hardest natural substance)
• Non-metals in different states: O₂, N₂, H₂ (gases), Br₂ (liquid), S, P, C (solids)

Chemical Properties of Metals

• Reaction with O₂: 4Na + O₂ → 2Na₂O; 2Mg + O₂ → 2MgO; Au/Ag/Pt do not react
• Reaction with water: Na → violent; Mg → steam only; Fe → on prolonged heating; Cu, Ag, Au → no reaction
• Reaction with acids: Zn + H₂SO₄ → ZnSO₄ + H₂; Cu does not react with dil. acid

Reactivity Series

• K > Na > Ca > Mg > Al > Zn > Fe > Ni > Sn > Pb > H > Cu > Hg > Ag > Au > Pt
• Uses: predict displacement reactions; determine extraction method for metals
• More reactive metal displaces less reactive from its salt solution

Ionic Bonding and Extraction

• Metals form ionic compounds with non-metals: electron transfer from metal to non-metal
• Highly reactive metals (Al, Na, K): electrolytic extraction; moderately reactive (Fe, Zn): reduction with C
• Thermite reaction: 2Al + Fe₂O₃ → Al₂O₃ + 2Fe (used in welding)

Corrosion

• Oxidation of metals in presence of moisture and oxygen; most common: rusting of iron
• Conditions for rusting: both O₂ and H₂O necessary; rust = Fe₂O₃·xH₂O
• Prevention: painting, oiling, galvanising, electroplating, alloying (stainless steel = Fe + Cr + Ni)

CBSE Exam Tips — Metals

• Activity: which metal burns with dazzling white flame in O₂ (magnesium)
• Define: alloy, amalgam, ore, gangue; give examples
• Compare sodium, magnesium and iron in reactions with cold water