Chapter: Metals and Non-Metals — Class 10 Science (NCERT)

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Chapter: Metals and Non-Metals — Class 10 Science (NCERT)

1. Introduction & Occurrence

• Metals: Elements that are generally lustrous (shiny), malleable, ductile, and good conductors of heat and electricity.
• Non-metals: Elements that are usually dull, brittle, and poor conductors of heat and electricity.
• Metals are generally solid at room temperature (except mercury).
• Non-metals can be solids, liquids, or gases at room temperature.
• In nature, metals occur in minerals. Those minerals from which metals can be extracted economically are called ores.

  (Sodium and Potassium are alkali-metals) [Alkali metals are a group of highly reactive, silvery-white, soft metals found in Group 1 of the periodic table. They include lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), and francium (Fr). These elements are characterized by their ability to readily lose their single valence electron, forming positive ions and reacting vigorously with water to produce alkaline hydroxides.]

2. Physical Properties

Metals

• Lustre: Have shiny surfaces that can be polished.
• Malleability: Can be hammered into thin sheets.
• Ductility: Can be drawn into wires.
• Conductivity: Good conductors of heat and electricity.
• Hardness: Generally hard.
• High melting/boiling points: Most metals have high melting and boiling points.

 

Non-Metals

• Appearance: Usually dull (except iodine).
• Brittleness: Break easily when hammered; non-malleable, non-ductile.
• Poor conductors: Do not conduct heat or electricity well (except graphite).
• Can be found in all states of matter at room temperature.
• Special cases: Diamond (very hard), graphite (conducts electricity), iodine (lustrous).

 

3. Chemical Properties & Reactivity

Metals

1.    Reaction with Oxygen:

o   Form basic oxides.

o   Example: 4 Mg + O₂ → 2 MgO.

2.    Reaction with Water:

o   React to form metal hydroxides and hydrogen gas.

o   Example: 2 Na + 2 H₂O → 2 NaOH + H₂↑.

3.    Reaction with Acids:

o   Produce salt and hydrogen gas.

o   Example: Zn + 2 HCl → ZnCl₂ + H₂↑.

4.    Reactivity Series:

o   Metals are arranged from most reactive (potassium) to least reactive (gold).

o   More reactive metals can displace less reactive metals from their compounds.

Non-Metals

• React with oxygen to form acidic or neutral oxides.
• Tend to gain electrons during reactions to form negative ions (anions).

 

4. Formation of Ionic Compounds

• Metals lose electrons to form positive ions (cations).
• Non-metals gain electrons to form negative ions (anions).
• Oppositely charged ions attract to form ionic compounds.
• Properties of ionic compounds:
• Hard and brittle.
• High melting and boiling points.
• Conduct electricity when molten or dissolved in water.

 

5. Extraction of Metals

Extraction is done in three main steps:

1.    Concentration of Ore:

o   Removing impurities (gangue) using methods like froth flotation, magnetic separation, or gravity separation.

2.    Conversion to Metal:

o   Roasting: Heating sulphide ores in air to form oxides.
Example: 2 ZnS + 3 O₂ → 2 ZnO + 2 SO₂↑.

o   Calcination: Heating carbonate ores in the absence of air to form oxides.
Example: ZnCO₃ → ZnO + CO₂↑.

o   Reduction: Heating oxides with a reducing agent like carbon to get the metal.

3.    Refining of Metals:

o   Electrolytic refining: Impure metal is made the anode, pure metal the cathode, and a suitable salt solution is used as electrolyte.

o   Example: Copper refining.

 

6. Corrosion and Prevention

• Corrosion: Gradual deterioration of metals due to reaction with air, moisture, or chemicals.
• Example: Rusting of iron.
• Prevention methods:
• Galvanization: Coating iron with zinc.
• Oiling/Greasing/Painting: Blocking contact with moisture and oxygen.
• Electroplating: Coating with a less reactive metal.
• Alloying: Mixing with other metals to improve corrosion resistance.

 7. Alloys

• Definition: Homogeneous mixtures of a metal with other metals or non-metals.
• Advantages: Greater strength, hardness, corrosion resistance, and better appearance.
• Examples:
• Steel = Iron + Carbon → Strong construction material.
• Stainless Steel = Iron + Chromium + Nickel → Rust-resistant.
• Brass = Copper + Zinc → Decorative items, utensils.
• Bronze = Copper + Tin → Medals, statues.
• Solder = Lead + Tin → Joining wires.
• Duralumin = Aluminium + Copper + Magnesium + Manganese → Aircraft parts.

 

8. Metalloids

• Elements that have properties of both metals and non-metals.
• Examples: Boron, Silicon, Arsenic, Tellurium, Germanium.

 

9. Real-Life Applications

• Metals: Used in construction (steel), transportation (aluminium), electrical wiring (copper), jewellery (gold, silver).
• Non-metals: Oxygen for respiration, nitrogen for fertilizers, chlorine for water purification, graphite for electrodes.

10. Quick Revision Table

Topic	Metals	Non-Metals
Lustre	Shiny	Dull (except iodine)
Malleability/Ductility	Malleable, ductile	Brittle
Conductivity	Good conductors	Poor conductors (except graphite)
Reaction with Oxygen	Basic oxides	Acidic/neutral oxides
Nature in Reactions	Lose electrons (form cations)	Gain electrons (form anions)
State at Room Temp	Mostly solids	Solid, liquid, or gas

 

Text Flow Chart - Metals & Non-Metals (Class 10 Science NCERT)
↓
Physical Properties
→ Metals: Lustrous, malleable, ductile, good conductors, generally high melting/boiling points.
→ Non-Metals: Dull (except iodine), brittle, poor conductors (except graphite), often low melting/boiling points.
↓
Chemical Properties
→ Metals: Form basic oxides, react with water & acids to release hydrogen gas, lose electrons to form cations.
→ Non-Metals: Form acidic or neutral oxides, gain electrons to form anions.
↓
Formation of Ionic Compounds
→ Metals lose electrons → Cations
→ Non-Metals gain electrons → Anions
→ Opposite charges attract → Ionic bond → Properties: Hard, high melting point, conduct electricity in molten or aqueous state.
↓
Extraction of Metals

1.    Concentration of Ore → Remove gangue/impurities.

2.    Conversion to Oxide → Roasting (sulphide ores) or Calcination (carbonate ores).

3.    Reduction → Obtain metal from oxide.

4.    Refining → Purify metal (e.g., Electrolytic refining).
↓
Corrosion & Prevention
→ Corrosion: Gradual damage due to reaction with environment (e.g., rusting of iron).
→ Prevention: Galvanization, oiling/painting, electroplating, alloying.
↓
Alloys
→ Mixtures of metals (sometimes with non-metals) for improved properties.
→ Examples: Steel, stainless steel, brass, bronze, solder, duralumin.
↓
Metalloids
→ Elements with both metallic and non-metallic properties (e.g., boron, silicon, arsenic).

 

NCERT CLASS 10 SCIENCE

Chapter: Metals and Non-Metals — Class 10 Science (NCERT).