CBSE Class 10 Science • Chapter 3 • Notes and Mind Map
Metals and Non-metals Class 10 Notes and Mind Map
The behaviour of an element helps explain its uses, the compounds it forms and the method used to extract it. These Metals and Non-metals Class 10 notes connect physical properties with reactivity, electron transfer, metallurgy and corrosion. Use the mind map to organise these connections for chapter revision.
Study the chapter through three questions: how does the material behave, how does it react, and how can it be obtained or protected? Following this sequence makes the reactivity series and extraction methods easier to understand.
Physical Properties: Connect Behaviour with Uses
Metals generally conduct heat and electricity, show lustre, and can be shaped without breaking. Malleability means the ability to form sheets; ductility means the ability to form wires. Solid non-metals are generally brittle and poor electrical conductors.
| Material | Relevant property | Connection with use |
|---|---|---|
| Copper | Electrical conductivity and ductility. | Suitable for electrical wiring. |
| Aluminium | Malleability and relatively low density. | Used in foil and lightweight components. |
| Gold | Lustre, malleability and low reactivity. | Useful in jewellery and decorative work. |
| Graphite | Conducts electricity despite being a non-metal. | Used in suitable electrode applications. |
Properties Have Exceptions
Mercury is liquid at room temperature. Sodium and potassium are soft metals. Iodine is lustrous, graphite conducts electricity, and diamond is exceptionally hard. Use several properties when comparing substances.
Chemical Properties of Metals Class 10
What Happens When Metals Form Oxides?
Many metals combine with oxygen to form oxides. Most metal oxides are basic, but aluminium oxide and zinc oxide are amphoteric: they react with both acids and bases.
Amphoteric Behaviour of Zinc Oxide
With an acid:
ZnO + 2HCl → ZnCl2 + H2O
With a base, using the conventional school equation:
ZnO + 2NaOH → Na2ZnO2 + H2O
These reactions show why zinc oxide cannot be described as only a basic oxide.
Reactions with Water and Acids
A metal’s reaction depends on the conditions as well as its identity. Sodium reacts vigorously with cold water. Magnesium reacts with hot water, while metals such as zinc and iron react with steam under suitable conditions.
Many metals above hydrogen in the reactivity series release hydrogen from dilute hydrochloric acid. This pattern should not be applied to every acid: oxidising acids can produce different outcomes.
The Reactivity Series as a Prediction Tool
K > Na > Ca > Mg > Al > Zn > Fe > Pb > H > Cu > Hg > Ag > Au
Reactivity generally decreases along this sequence. Hydrogen provides a reference for comparing reactions with dilute non-oxidising acids.
The series helps predict displacement: a more reactive metal can replace a less reactive metal from an appropriate salt solution. It also helps explain why extraction methods differ.
Read a Displacement Equation
Zn + CuSO4 → ZnSO4 + Cu
Zinc enters the compound and copper is released. This indicates that zinc is more reactive than copper. The reverse displacement does not occur under ordinary conditions.
Ionic Bonding: From Electrons to a Crystal
In a simple ionic model, a metal transfers electrons to a non-metal. The resulting positive and negative ions attract one another. In the solid, they form an extended ionic lattice rather than separate pairs of molecules.
Why Is the Formula of Sodium Oxide Na₂O?
Each sodium atom loses one electron to form Na+. An oxygen atom gains two electrons to form O2−.
Two Na+ ions balance the charge of one O2− ion. The electrically neutral ratio is therefore 2 : 1, giving Na2O.
Explain Ionic Properties Using the Structure
- High melting points: strong attractions between oppositely charged ions require substantial energy to overcome.
- No conduction in the solid: ions remain in fixed lattice positions.
- Conduction when molten: ions become mobile and carry charge.
- Conduction in solution: dissolved mobile ions carry charge.
Identify the Correct Charge Carriers
Metals conduct mainly through mobile electrons. Molten ionic compounds and their conducting aqueous solutions carry charge through mobile ions. Do not explain both using “free electrons.”
Extraction of Metals: Follow the Reactivity
Minerals are naturally occurring substances containing metals or their compounds. An ore is a mineral deposit from which a metal can be extracted economically. Unwanted earthy material associated with an ore is commonly called gangue.
A useful revision sequence is concentration of the ore, conversion into a suitable compound, reduction to the metal, and refining. The exact steps vary with the ore and extraction process.
| Group | Examples | Main idea |
|---|---|---|
| Highly reactive metals | Sodium, magnesium, aluminium. | Electrical energy reduces ions in suitable molten electrolytes. |
| Moderately reactive metals | Zinc, iron, lead. | Suitable ores are commonly converted into oxides and chemically reduced. |
| Low-reactivity metals | Copper, mercury, silver, gold. | Some compounds yield metals on heating; some metals also occur in the native state. |
Roasting and Calcination
Roasting heats sulphide ores in excess air. Calcination heats suitable carbonate or hydrated ores in limited or no air. Both can prepare an oxide for a later reduction step.
Roasting:
2ZnS + 3O2 → 2ZnO + 2SO2
Calcination:
ZnCO3 → ZnO + CO2
Reduction on heating:
ZnO + C → Zn + CO
The Thermit Reaction
Aluminium can reduce iron(III) oxide, releasing considerable heat. The hot iron produced can be used in suitable welding applications.
Fe2O3 + 2Al → 2Fe + Al2O3 + heat
Electrolytic Refining of Copper
Refining increases the purity of a metal. In copper refining, impure copper forms the anode, pure copper forms the cathode, and acidified copper sulphate solution is the electrolyte.
At the anode:
Cu → Cu2+ + 2e−
At the cathode:
Cu2+ + 2e− → Cu
Copper transfers from the impure anode to the cathode. Insoluble impurities collect as anode mud.
Corrosion, Protection and Alloys
Corrosion involves chemical deterioration through interaction with the surroundings. Iron rusts in the presence of oxygen and water. Aluminium, although reactive, develops an oxide film that helps limit further corrosion.
Protection can work by separating a metal from its surroundings or changing its surface behaviour. Painting provides a barrier, galvanisation uses zinc, and alloying can improve useful properties.
An alloy is a mixture of metals, or of a metal with another element. Brass contains copper and zinc; bronze contains copper and tin. Alloy properties differ from those of their constituents.
How to Use the Metals and Non-metals Mind Map
Use the mind map to connect a property with its chemical explanation and practical consequence. Follow one branch at a time and recall an example without looking at the detailed notes.
- Physical properties: connect conductivity, malleability and ductility with uses and exceptions.
- Chemical behaviour: connect oxygen, water and acid reactions with conditions.
- Reactivity: predict displacement and compare extraction methods.
- Ionic compounds: connect electron transfer with charge balance and properties.
- Metallurgy: distinguish concentration, conversion, reduction and refining.
- Protection: connect corrosion with coatings and alloys.
Pay particular attention to the connection between the reactivity series and extraction. This turns two sections of the chapter into one connected explanation.
Frequently Asked Questions
Why do ionic compounds have high melting points?
Their lattices contain strong electrostatic attractions between oppositely charged ions. Considerable energy is needed to overcome these attractions.
Why can molten ionic compounds conduct electricity?
Their ions can move and carry charge. In the solid, the ions are fixed in the lattice and cannot provide the same charge flow.
Why are sulphide and carbonate ores often converted into oxides?
For the relevant moderately reactive metals, their oxides are more convenient to reduce using the chosen chemical reducing agents.
How can I distinguish roasting from calcination?
Check both the ore and air supply. Roasting commonly treats sulphides in excess air; calcination commonly treats carbonates or hydrated ores with limited or no air.
Why cannot carbon extract every metal from its oxide?
Some highly reactive metals form very stable compounds. Carbon is not an effective reducing agent for those extraction conditions, so electrolytic methods are used.
What is the difference between extraction and refining?
Extraction obtains a metal from its source material. Refining removes impurities from the metal already obtained.
Why is aluminium used in the thermit reaction?
Aluminium has a strong affinity for oxygen and can reduce iron(III) oxide. The reaction releases enough heat to produce very hot iron.
Are all metal oxides basic?
No. Aluminium oxide and zinc oxide are important amphoteric examples that react with acids and bases.
Does an ionic compound consist of separate molecules?
A typical solid ionic compound forms an extended lattice. Its formula gives the simplest ratio of ions rather than describing a separate molecule.
How does the mind map help with metallurgy revision?
It helps you follow the sequence from ore to refined metal and connect each extraction route with reactivity. Explain why each step is needed as you revise.
Download
