Metals and Non-Metals – Class 10 Chemistry Chapter 3

Metals and Non-Metals

Elements are broadly classified into metals and non-metals based on their physical and chemical properties.

Physical Properties of Metals

• Lustrous (shiny surface when freshly cut)
• Malleable (can be beaten into thin sheets — gold, aluminium)
• Ductile (can be drawn into wires — copper, aluminium)
• Good conductors of heat and electricity (silver is the best conductor)
• Generally hard (exception: sodium and potassium are soft)
• High melting and boiling points (exception: gallium and caesium melt at body temperature)
• Produce a sonorous (ringing) sound when struck

Physical Properties of Non-Metals

• Non-lustrous, dull appearance (exception: iodine is lustrous, diamond has exceptional lustre)
• Brittle — cannot be drawn into wires or sheets
• Poor conductors of heat and electricity (exception: graphite conducts electricity)
• Generally low density, melting, and boiling points

Reactivity Series of Metals

The reactivity series arranges metals in decreasing order of reactivity:

K > Na > Ca > Mg > Al > Zn > Fe > Ni > Sn > Pb > H > Cu > Hg > Ag > Au > Pt

A more reactive metal can displace a less reactive metal from its compound in solution.

Ionic Bonding

Metals transfer electrons to non-metals, forming ionic compounds (e.g., NaCl). Ionic compounds have high melting points, are soluble in water, and conduct electricity when dissolved or melted.

Extraction of Metals

The method of extraction depends on reactivity:

Reactivity	Method	Examples
High (K, Na, Ca, Mg, Al)	Electrolytic reduction	Aluminium from bauxite
Medium (Zn, Fe, Ni, Sn, Pb)	Reduction with carbon (coke)	Iron from haematite
Low (Cu, Hg, Ag, Au)	Self-reduction / Roasting	Copper from Cu₂S

Corrosion

When metals are exposed to moisture, acids, or gases, they corrode. Rusting of iron (forming Fe₂O₃·xH₂O) is the most common example. Prevention methods include painting, oiling, galvanisation (zinc coating), electroplating, and alloying.

Reference: NCERT Science Textbook for Class 10 – Chapter 3; Pradeep's Chemistry.