๐Ÿงช Metals and Non-metals ๐Ÿงช

Class X Chemistry โ€ข Chapter 3 โ€ข NCERT Enhanced

๐Ÿ”ฌ Introduction

Elements are broadly classified into metals and non-metals based on their physical and chemical properties. This classification helps us understand their behavior, applications, and role in our daily lives.

๐Ÿ’ก Did You Know?

Out of 118 known elements, about 78 are metals! Metals make up most of the periodic table and are essential for life and technology.

โšก Physical Properties

MMetallic Luster

Metals: Shiny appearance when freshly cut (e.g., silver, gold)

Non-metals: Dull appearance (except iodine and graphite)

๐Ÿ”จMalleability

Metals: Can be hammered into thin sheets

Non-metals: Brittle, break when hammered

๐Ÿ“Ductility

Metals: Can be drawn into wires

Non-metals: Cannot be drawn into wires

โšกConductivity

Metals: Good conductors of heat and electricity

Non-metals: Poor conductors (except graphite)

๐Ÿ”ŠSonority

Metals: Produce sound when struck

Non-metals: Do not produce sound

๐Ÿ—๏ธDensity

Metals: Generally high density

Non-metals: Generally low density

๐ŸŽฏ Key Points to Remember

  • Gold is the most malleable metal - can be beaten into sheets 0.0001 mm thick
  • Silver is the best conductor of heat and electricity
  • Graphite is the only non-metal that conducts electricity
  • Iodine is the only non-metal with metallic luster
  • Mercury is the only metal that is liquid at room temperature

๐Ÿงช Chemical Properties

1. Reaction with Oxygen

Most metals react with oxygen to form metal oxides, which are generally basic in nature.

Metal + Oxygen โ†’ Metal Oxide

4Na + O2 โ†’ 2Na2O
2Mg + O2 โ†’ 2MgO
4Al + 3O2 โ†’ 2Al2O3

Non-metals react with oxygen to form non-metal oxides, which are generally acidic in nature.

Non-metal + Oxygen โ†’ Non-metal Oxide

C + O2 โ†’ CO2
S + O2 โ†’ SO2
4P + 5O2 โ†’ 2P2O5

2. Reaction with Water

Metals react with water to produce metal hydroxides and hydrogen gas.

Metal + Water โ†’ Metal Hydroxide + Hydrogen

2Na + 2H2O โ†’ 2NaOH + H2 โ†‘
2K + 2H2O โ†’ 2KOH + H2 โ†‘
Ca + 2H2O โ†’ Ca(OH)2 + H2 โ†‘

โš ๏ธSafety Note

Alkali metals (Na, K) react violently with water and can cause explosions. Always handle with extreme care!

3. Reaction with Acids

Metals above hydrogen in the reactivity series react with acids to produce salt and hydrogen gas.

Metal + Acid โ†’ Salt + Hydrogen

Zn + 2HCl โ†’ ZnCl2 + H2 โ†‘
Mg + H2SO4 โ†’ MgSO4 + H2 โ†‘
Fe + 2HCl โ†’ FeCl2 + H2 โ†‘

4. Reaction with Bases

Some metals react with bases to produce salt and hydrogen gas.

Metal + Base โ†’ Salt + Hydrogen

2Al + 2NaOH + 6H2O โ†’ 2Na[Al(OH)4] + 3H2 โ†‘
Zn + 2NaOH โ†’ Na2ZnO2 + H2 โ†‘

๐Ÿ“Š Comparison Table

Property Metals Non-metals
Physical State Solid (except Hg) Solid, liquid, or gas
Luster Shiny (metallic luster) Dull (except I2, graphite)
Malleability Malleable Brittle
Ductility Ductile Non-ductile
Conductivity Good conductor Poor conductor (except graphite)
Sonority Sonorous Non-sonorous
Density High Low
Melting Point Generally high Generally low
Oxides Basic oxides Acidic oxides
Electrons Lose electrons (cations) Gain electrons (anions)

๐Ÿ”„ Reactivity Series

The reactivity series is an arrangement of metals in order of their decreasing reactivity.

๐Ÿ“ˆ Reactivity Series (Most to Least Reactive)

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

๐ŸŽฏ Important Points

  • Metals above hydrogen can displace hydrogen from acids
  • More reactive metals can displace less reactive metals from their salts
  • Metals below hydrogen (Cu, Hg, Ag, Au) do not react with dilute acids
  • Aqua regia (3:1 HCl:HNO3) can dissolve even gold and platinum

๐Ÿญ Occurrence of Metals

1. Native State

Unreactive metals like gold, silver, and platinum are found in free state in nature.

2. Combined State

Most metals are found in combined state as:

๐Ÿ”Activity 3.1: Testing Metals

Aim: To test the physical properties of metals

Materials: Iron nail, copper wire, aluminum foil, zinc granules

Procedure:

  1. Test the luster of each metal
  2. Try to bend or hammer each metal
  3. Test conductivity using a simple circuit
  4. Strike each metal and listen for sound

Observation: All metals show metallic luster, malleability, conductivity, and sonority.

โš—๏ธ Extraction of Metals

1. Concentration of Ores

Removal of impurities from ore to get concentrated ore.

2. Reduction

Conversion of metal oxides to free metals using reducing agents.

Metal Oxide + Reducing Agent โ†’ Metal + Oxidized Product

ZnO + C โ†’ Zn + CO
Fe2O3 + 3CO โ†’ 2Fe + 3CO2
2Al2O3 โ†’ 4Al + 3O2 (Electrolysis)

3. Refining

Purification of crude metal to remove impurities.

๐ŸŽฏ Methods of Extraction

  • Highly reactive metals (K, Na, Ca, Mg, Al): Electrolysis
  • Moderately reactive metals (Zn, Fe, Pb): Reduction with carbon
  • Less reactive metals (Cu, Hg): Roasting
  • Least reactive metals (Ag, Au): No reduction needed

๐Ÿ›ก๏ธ Corrosion

Corrosion is the gradual destruction of metals due to chemical reaction with environment.

Rusting of Iron:
4Fe + 3O2 + 2xH2O โ†’ 2Fe2O3.xH2O

(Hydrated Iron(III) oxide - Rust)

Prevention of Corrosion

๐ŸŽจPainting

Coating with paint prevents contact with air and moisture

๐Ÿ›ข๏ธOiling/Greasing

Applying oil or grease creates protective layer

โšกGalvanization

Coating iron with zinc prevents rusting

๐Ÿ”งAlloying

Mixing metals to improve properties and reduce corrosion

๐Ÿ”— Alloys

Alloys are homogeneous mixtures of metals with other metals or non-metals.

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๐Ÿ“š freetestmaker.com | Anonymous | 2025-10-31 22:02:03
Alloy Composition Properties Uses
Steel Fe + C (0.1-1.5%) Hard, strong, malleable Construction, tools
Stainless Steel Fe + Cr + Ni Corrosion resistant Utensils, surgical instruments
Brass Cu + Zn Malleable, corrosion resistant Decorative items, musical instruments
Bronze Cu + Sn Hard, corrosion resistant