Properties of Metals & Non-metals

• Physical properties — lustre, malleability, ductility, conductivity, sonority (metals).
• Exceptions — mercury liquid; iodine lustrous non-metal; graphite conducts.
• Chemical properties — reaction with O₂, water, acids; oxide nature.
• Metalloids — silicon, germanium — intermediate properties.
• Alloys — homogeneous mixture improving properties (steel, brass, bronze).

1. Metals — generally shiny, malleable, ductile, good heat/electric conductors.
2. Non-metals — dull (except iodine), brittle solids or gases, poor conductors (except graphite).
3. Metal + O₂ — basic oxides (Na₂O, MgO); some amphoteric (Al, Zn).
4. Non-metal + O₂ — acidic or neutral oxides (SO₂, CO₂, H₂O).
5. Reaction with water — Na vigorous; Mg slow; Fe/Cu negligible cold.
6. Reaction with acids — metal + acid → salt + H₂ (above H in activity series).
7. Sonority — metals ring when struck.
8. Alloys — stainless steel (Fe+Cr+Ni), brass (Cu+Zn), 22-carat gold.
9. Ionic bonding — metal + non-metal typically ionic compound.
10. NCERT exceptions — always mention when generalising properties.

Compare copper and sulphur on conductivity and malleability

Copper (metal):
- Conducts electricity well (free electrons)
- Malleable — can be hammered into sheets
Sulphur (non-metal):
- Poor conductor (except graphite allotrope of C)
- Brittle — breaks when hammered
Conclusion: copper shows typical metal properties; sulphur typical non-metal.

• Saying all metals react with cold water (only reactive ones like Na, K).
• Misconception: non-metals never conduct (graphite, gaseous ions in discharge).
• Forgetting mercury is liquid metal at room temperature.
• Confusing malleability with ductility (sheet vs wire).
• Assuming all metal oxides basic (Al₂O₃ amphoteric).

• List four physical properties of metals.
• Which non-metal is lustrous?
• What is an alloy? Give one example.
• Do metals conduct heat? Why?

Open the Practice tab for graded questions on Properties of Metals & Non-metals.