Exhaustive Academic Study Notes on Metals and Non-Metals

Physical Properties of Metals and Non-Metals

• General Physical Characteristics of Metals:

  • State: Most metals exist as solids at room temperature.

  • Appearance: Metals typically possess a shiny, lustrous appearance.

  • Hardness: Metals are generally hard.

  • Malleability: Metals exhibit malleability, meaning they can be beaten or hammered into thin sheets without shattering.

  • Ductility: Metals possess ductility, which allows them to be drawn or stretched into thin wires.

  • Conductivity: Metals are excellent conductors of both heat and electricity.

  • Sonority: Metals are sonorous, producing a deep ringing sound when struck with a hard object.

• General Physical Characteristics of Non-Metals:

  • State: Non-metals exist mostly in solid or gaseous states at room temperature.

  • Hardness & Texture: Solid non-metals are soft and brittle, crumbling or breaking easily when subjected to stress.

  • Appearance: Non-metals generally lack luster and appear dull.

  • Conductivity: Non-metals are poor conductors (insulators) of heat and electricity, with specific exceptions such as graphite and diamond.

• Specific Property Applications:

  • Wind Chimes and Musical Instruments: Made from metals due to their property of sonority.

  • Electrical Wires: Made from metals like copper due to high electrical conductivity and ductility.

  • Decorative Articles and Jewellery: Made from metals like gold, silver, and platinum due to their metallic luster, malleability, and resistance to tarnish.

  • Cooking Utensils: Made from metals like copper and aluminium because they are good thermal conductors.

Chemical Reactions of Metals and Non-Metals

• Reactions with Oxygen:

  • Metals: Combine with oxygen to form metallic oxides, which are basic in nature and turn red litmus solution blue.

$\text{metal} + \text{oxygen} \rightarrow \text{metal oxide}$

*   *Sodium Reaction:* Sodium reacts vigorously with atmospheric oxygen at room temperature to form sodium oxide, catching fire if left exposed in the open. It must be kept stored immersed in kerosene.

$4Na + O_2 \rightarrow 2Na_2O$

*   *Magnesium Reaction:* Magnesium ribbon burns in air upon heating with a dazzling white light to yield magnesium oxide.

$2Mg + O_2 \rightarrow 2MgO$

*   **Non-Metals:** React with oxygen to produce non-metallic oxides (also called acidic oxides). When dissolved in water, these oxides form acids that turn blue litmus paper red.

$\text{non-metal} + \text{oxygen} \rightarrow \text{non-metallic oxide}$

*   *Carbon Reaction:* Carbon burns in air to produce carbon dioxide gas.

$C + O_2 \rightarrow CO_2$

*   *Sulphur Reaction:* Sulphur burns in air to produce sulphur dioxide, a gas with a strong, sharp, pungent, and suffocating smell.

$S + O_2 \rightarrow SO_2$

*   *Dissolution of Acidic Oxides in Water:* Non-metallic oxides dissolve in water to form corresponding acids.

$CO_2 + H_2O \rightarrow H_2CO_3$

$SO_2 + H_2O \rightarrow H_2SO_3$

• Reactions with Water:

  • Metals: Most metals react with water to form metal hydroxides or metal oxides alongside hydrogen gas.

$\text{metal} + \text{water} \rightarrow \text{metal hydroxide} + \text{hydrogen gas}$

$\text{metal} + \text{water} \rightarrow \text{metal oxide} + \text{hydrogen gas}$

*   *Sodium Reaction:* Sodium reacts violently with cold water to produce sodium hydroxide solution and hydrogen gas. The reaction releases a large quantity of heat, causing the evolved hydrogen gas to catch fire immediately.

$2Na + 2H_2O \rightarrow 2NaOH + H_2$

*   *Unreactive Metals:* Metals such as copper, silver, and gold do not react with water under any environmental conditions.
*   **Non-Metals:** Non-metals generally do not react with water.
*   *Storage of Phosphorus:* Phosphorus is a highly reactive non-metal that spontaneously ignites in air upon exposure to oxygen. To prevent contact with atmospheric oxygen, it is stored under water.

• Reactions with Acids:

  • Metals: Metals react with acids to produce corresponding salts and hydrogen gas. Reaction rates vary from fast and vigorous to extremely slow depending on the reactivity of the metal.

$\text{metal} + \text{acid} \rightarrow \text{salt} + \text{hydrogen gas}$

*   *Zinc and Sulphuric Acid:* Zinc reacts with dilute sulphuric acid to yield zinc sulphate and hydrogen gas.

$Zn + H_2SO_4 \rightarrow ZnSO_4 + H_2$

*   *Magnesium and Sulphuric Acid:* Magnesium reacts with dilute sulphuric acid to yield magnesium sulphate and hydrogen gas.

$Mg + H_2SO_4 \rightarrow MgSO_4 + H_2$

*   *Aluminium and Hydrochloric Acid:* Aluminium reacts with hydrochloric acid to yield aluminium chloride and hydrogen gas.

$2Al + 6HCl \rightarrow 2AlCl_3 + 3H_2$

*   **Non-Metals:** Non-metals generally do not react with acids.

• Reactions with Bases:

  • Metals: Most metals do not react with bases. Only specific metals like aluminium, zinc, and lead react with solutions of strong bases such as sodium hydroxide ($NaOH$) to evolve hydrogen gas and form complex metal salts.

  • Non-Metals: The reactions of non-metals with bases are highly complex.

Reactivity Series and Displacement Reactions

• Definition of Reactivity Series: The reactivity series of metals is an arrangement of common metals in decreasing order of their chemical reactivity.

• Reactivity Series Order (Most Reactive to Least Reactive):

  1. Potassium ($K$) - Most reactive

  2. Sodium ($Na$)

  3. Calcium ($Ca$)

  4. Magnesium ($Mg$)

  5. Aluminium ($Al$)

  6. Zinc ($Zn$)

  7. Iron ($Fe$)

  8. Tin ($Sn$)

  9. Lead ($Pb$)

  10. Hydrogen ($H$)

  11. Copper ($Cu$)

  12. Mercury ($Hg$)

  13. Silver ($Ag$)

  14. Gold ($Au$)

  15. Platinum ($Pt$) - Least reactive

• Principles of Displacement Reactions:

  • A displacement reaction occurs when a more reactive metal displaces a less reactive metal from its salt solution.

  • A metal placed higher in the reactivity series can displace any metal placed below it from its salt solution.

  • A metal placed lower in the series cannot displace a metal placed above it.

• Displacement Examples:

  • Zinc and Copper Sulphate: Zinc is higher than copper in the series, so zinc displaces copper.

$Zn + CuSO_4 \rightarrow ZnSO_4 + Cu$

*   *Silver and Zinc Sulphate:* Silver is lower than zinc, so no reaction occurs.

$Ag + ZnSO_4 \rightarrow \text{No reaction}$

*   *Silver and Copper Sulphate:* Silver is lower than copper, so no reaction occurs.

$Ag + CuSO_4 \rightarrow \text{No reaction}$

*   *Iron and Copper Sulphate:* Iron displaces copper to form iron sulphate ($FeSO_4$) and copper deposit.

*   *Relative Reactivity Order Derived:* Based on displacement capabilities, the reactivity order of zinc, copper, and silver is:

$Zn > Cu > Ag$

Corrosion Processes and Examples

• Definition: Corrosion is the process of slow wearing away of a metal surface due to chemical attack by atmospheric gases and moisture.

• Corrosion of Iron (Rusting):

  • Iron reacts with atmospheric oxygen and moisture to form a brown, flaky coating called rust.

  • Rusting causes structural weakness because the flaky rust continually falls off, exposing fresh underlying iron to further oxidation.

• Corrosion of Copper:

  • Over time, copper objects exposed to atmospheric carbon dioxide and moisture form a green surface coating.

  • This green substance consists of basic copper carbonate, represented chemically as a mixture of copper carbonate and copper hydroxide:

$CuCO_3 \cdot Cu(OH)_2$

• Corrosion of Silver:

  • Silver objects lose their metallic luster and blacken over time.

  • This tarnishing occurs due to reaction with hydrogen sulphide ($H_2S$) gas present in the air, forming black silver sulfide ($Ag_2S$).

Practical Uses of Metals and Non-Metals

• Uses of Metals:

  • Iron: Heavy machinery, building materials, automobiles, wrought iron furniture, cast iron rods, gates, window/door grills, shipping containers, railway tracks, nuts, bolts, nails, pipes, and tools.

  • Steel: Used in building materials, nails, and screws due to its high tensile strength.

  • Copper: Electrical wires, cables, coils, pipe fittings, electrical equipment components, cooking utensils, integrated circuits, and electromagnets.

  • Aluminium: Machinery parts, automobiles, building structures (sheets, rods, door and window frames), household utensils, packaging tins and cans, streetlight poles, and thin wrapping foils.

  • Zinc: Iron coating to prevent rusting (galvanization) and formulation of alloys with metals like aluminium and lead.

  • Mercury: Used in temperature measuring devices (thermometers) and as amalgams for dental fillings.

  • Lead: Car batteries, pigments, and paints.

  • Gold, Silver, Platinum: Jewellery, decorative items, and high-end cutlery.

• Uses of Non-Metals:

  • Diamond (Carbon allotrope): High-end jewellery, industrial cutting tools, and heavy drilling equipment due to its supreme hardness.

  • Graphite (Carbon allotrope): Pencil lead manufacture, powdered lubricant for high-temperature machine parts, and electrode rods in zinc-carbon batteries.

  • Hydrogen: Industrial synthesis of ammonia ($NH_3$) and methyl alcohol ($CH_3OH$), welding torches, metal extraction processes, and non-polluting clean fuel.

  • Sulphur: Rubber vulcanization (hardening), synthesis of sulphuric acid ($H_2SO_4$) and sulphates, manufacture of matchsticks, dyes, gunpowder, fungicides, and insecticides.

  • Silicon: Major constituent of sand, widely used in electronic semiconductors, microchips, solar panels, and transistors.

  • Phosphorus: Matchsticks, pyrotechnics (fireworks), and agricultural phosphate fertilizers.

  • Nitrogen: Synthesis of ammonia and nitrate fertilizers, food preservation and packaging (e.g., filling chip bags to prevent oxidation), and liquid nitrogen for cryo-refrigeration of biological cells in medical research.

  • Oxygen: Pressurized cylinders for high-altitude mountaineers and deep-sea divers, commercial steel manufacture, synthesis of nitric acid ($HNO_3$) and hydrogen peroxide ($H_2O_2$), and oxyacetylene cutting/welding torches.

Alloys and Technical Specifications

• Definition: An alloy is a homogeneous mixture of two or more metals, or a metal and a non-metal.

• Properties: Alloys exhibit superior properties compared to their parent components, including enhanced strength, hardness, and elevated resistance to corrosion.

• Examples of Alloys:

  • Stainless Steel: Composed of Iron ($Fe$), Nickel ($Ni$), and Chromium ($Cr$).

  • Bronze: Composed of Copper ($Cu$) and Tin ($Sn$).

  • Steel: Iron alloyed with small amounts of carbon.

Key Definitions and Terminology

• Malleability: The property by virtue of which metals can be beaten into thin sheets.

• Ductility: The property by virtue of which metals can be drawn into thin wires.

• Sonority: The property by virtue of which metal objects produce a ringing sound when struck with a hard object.

• Corrosion: The process of slow wearing away of a metal due to the attack of atmospheric gases and moisture on its surface.

• Salts: Compounds formed when a metal replaces hydrogen in an acid.

• Reactivity Series of Metals: A list of common metals arranged in decreasing order of reactivity.

• Galvanization: The process of coating iron objects with a thin layer of zinc to prevent rusting.

• Pungent: Having a strong, sharp, piercing smell.

Experimental Activities and Demonstrations

• Synthesis and Litmus Testing of a Non-Metallic Oxide:

  • Materials: Sulphur, deflagrating spoon, burner, gas jar with lid, water ($20\,mL$), blue litmus paper.

  • Procedure: Heat sulphur in a deflagrating spoon until burning starts. Lower into gas jar and cover partly. Once filled with sulphur dioxide ($SO_2$), remove spoon and seal. Add $20\,mL$ of water to dissolve the gas, then insert blue litmus paper.

  • Observation: Blue litmus paper turns red.

  • Conclusion: Sulphur dioxide gas dissolves in water forming sulphurous acid ($H_2SO_3$), demonstrating that non-metallic oxides are acidic in nature.

• Demonstration of Hydrogen Gas Production from Metal-Acid Reaction:

  • Materials: Magnesium ribbon, dilute sulphuric acid ($H_2SO_4$), test tube, dropper, matchstick.

  • Procedure: Place magnesium ribbon inside a test tube. Add dilute sulphuric acid using a dropper. Bring a burning matchstick near the mouth of the test tube.

  • Observation: Gas evolves and burns with a characteristic 'pop' sound upon contact with the flame.

  • Conclusion: The gas generated by the reaction between magnesium and sulphuric acid is hydrogen gas.

• Iron vs. Copper Displacement Reaction Activity:

  • Materials: Iron filings, copper turnings, copper sulphate ($CuSO_4$) solution, iron sulphate ($FeSO_4$) solution, two test tubes (labelled A and B), dropper.

  • Procedure: Add copper sulphate solution to iron filings in Test Tube A. Add iron sulphate solution to copper turnings in Test Tube B.

  • Observation: In Test Tube A, iron filings develop a brown copper coating and the solution changes from blue to pale green ($FeSO_4$). In Test Tube B, no color change or reaction occurs.

  • Conclusion: Iron is more reactive than copper and displaces copper from copper sulphate solution.

Real-World Case Studies and Historical Wonders

• The Iron Pillar near Qutub Minar (Delhi):

  • Stands as a historic metallurgical wonder evaluated by global archaeologists and scientists.

  • Has successfully resisted atmospheric corrosion and rusting for over $1600\,years$ despite constant exposure to harsh weather conditions.

• The Statue of Unity:

  • Recognized as the world's tallest statue, reaching an overall height of $182\,m$.

  • Located in Gujarat on a river island facing the Sardar Sarovar Dam on the Narmada River.

  • Constructed using cement-concrete, $18,500\,tonnes$ of reinforced steel, $6,500\,tonnes$ of structural steel, $1,700\,tonnes$ of bronze, and $1,850\,tonnes$ of bronze cladding.

• Health Impact of Heavy Metals (Mercury Exposure):

  • Environmental contamination of water bodies with heavy metals such as mercury causes severe human toxicity.

  • In children, mercury toxicity leads to condition-specific clinical symptoms including pink coloration of the skin and cutaneous peeling.

Review Exercises and Solutions

• Multiple Choice Questions:

  1. Copper is a: d. reddish-brown metal

  2. A soft metal that can be cut with a knife is: b. potassium (or sodium)

  3. The property of metals due to which they can be drawn into thin wires is: ** ductility**

  4. Which of the following is a good conductor of heat? d. All of these (Diamond, Silver)

  5. The order of reactivity of metals is: c. $Mg > Zn > Fe > Cu$

  6. A metal that will displace copper from copper sulphate solution is: c. aluminium

  7. Which gas is produced in the reaction of a metal with an acid? d. Hydrogen

  8. Which of the following is the least reactive metal? a. Gold

  9. Which metal is used in paints and pigments? b. Lead

  10. Which non-metal is used for making matchsticks and fireworks? c. Phosphorus

• Fill in the Blanks:

  1. The property of metals due to which they produce a ringing sound when struck with a hard object is called sonority.

  2. A non-metal that is a good conductor of heat is diamond (or graphite for electrical conductivity).

  3. A metal that burns with white dazzling light is magnesium.

  4. Metallic oxides turn red litmus solution to blue.

  5. Sodium is kept immersed in kerosene.

  6. Non-metallic oxides dissolve in water to form acids.

  7. Galvanization is the process of coating iron with zinc to prevent rusting.

  8. Graphite (in powdered form) is used as a lubricant for machine parts.

  9. Phosphorus is used in making matchsticks and fireworks.

  10. Steel is an alloy of iron used for making building materials, nails and screws.

  11. Lead is used in car batteries, pigments and paints.

  12. Hydrogen can be used as a non-polluting fuel.

  13. Liquid Nitrogen is used for refrigerating cells for medical research.

• Chemical Equations Completion:

$4Na + O_2 \rightarrow 2Na_2O$

$S + O_2 \rightarrow SO_2$

$2Na + 2H_2O \rightarrow 2NaOH + H_2$