Chemistry · Class 9-10 · CBSE
Metals, Non-Metals and the Reactivity Series
Explore physical and chemical properties of metals vs non-metals, the metal reactivity series, ionic bond formation in NaCl and MgCl2, properties of electrovalent compounds, and basic metallurgical processes.
1Physical and Chemical Properties Comparison
Elements are broadly classified intoMetals(electropositive elements that lose electrons to form cations) andNon-Metals(electronegative elements that gain electrons to form anions).
Metals vs Non-Metals: Physical Properties & Exceptions
| Property | Metals | Non-Metals | Important Exceptions |
|---|---|---|---|
| Physical State | Solids at room temperature | Solids and gases | Mercury (Hg) is liquid metal; Bromine (Br₂) is liquid non-metal |
| Malleability & Ductility | Highly malleable (beaten into foils) & ductile (drawn to wires) | Brittle (shatter when hammered) | Gold & silver are most malleable/ductile; Zinc is brittle |
| Electrical Conductivity | Good conductors (free sea of electrons) | Poor conductors / insulators | Graphite (carbon allotrope) is an excellent conductor of electricity |
| Hardness & Melting Point | Generally hard with high melting points | Soft with low melting points | Sodium, Potassium are soft metals cut with knife; Diamond is hardest natural substance |
| Lustre | Metallic shine (lustrous) | Dull appearance | Iodine (I₂) is a lustrous non-metal |
Physical State
- Metals
- Solids at room temperature
- Non-Metals
- Solids and gases
- Important Exceptions
- Mercury (Hg) is liquid metal; Bromine (Br₂) is liquid non-metal
Malleability & Ductility
- Metals
- Highly malleable (beaten into foils) & ductile (drawn to wires)
- Non-Metals
- Brittle (shatter when hammered)
- Important Exceptions
- Gold & silver are most malleable/ductile; Zinc is brittle
Electrical Conductivity
- Metals
- Good conductors (free sea of electrons)
- Non-Metals
- Poor conductors / insulators
- Important Exceptions
- Graphite (carbon allotrope) is an excellent conductor of electricity
Hardness & Melting Point
- Metals
- Generally hard with high melting points
- Non-Metals
- Soft with low melting points
- Important Exceptions
- Sodium, Potassium are soft metals cut with knife; Diamond is hardest natural substance
Lustre
- Metals
- Metallic shine (lustrous)
- Non-Metals
- Dull appearance
- Important Exceptions
- Iodine (I₂) is a lustrous non-metal
2Reactivity Series and Chemical Reactions
The Reactivity (Activity) Series of Metals
| Metal Name | Chemical Symbol | Reaction with Cold Water | Reaction with Dilute Acids |
|---|---|---|---|
| Potassium & Sodium | K, Na | Violent reaction releasing H₂ gas that catches fire immediately | Extremely explosive reaction |
| Calcium & Magnesium | Ca, Mg | Ca reacts with cold water; Mg reacts with hot water/steam | Rapid evolution of H₂ gas |
| Aluminium, Zinc, Iron | Al, Zn, Fe | Do not react with cold/hot water; react with steam only | Moderate evolution of H₂ gas |
| Lead, Hydrogen, Copper | Pb, H, Cu | No reaction with water or steam | No reaction with dilute HCl / H₂SO₄ |
| Silver & Gold | Ag, Au | Completely unreactive with water or steam | Completely inert (dissolve only in Aqua Regia) |
Potassium & Sodium
- Chemical Symbol
- K, Na
- Reaction with Cold Water
- Violent reaction releasing H₂ gas that catches fire immediately
- Reaction with Dilute Acids
- Extremely explosive reaction
Calcium & Magnesium
- Chemical Symbol
- Ca, Mg
- Reaction with Cold Water
- Ca reacts with cold water; Mg reacts with hot water/steam
- Reaction with Dilute Acids
- Rapid evolution of H₂ gas
Aluminium, Zinc, Iron
- Chemical Symbol
- Al, Zn, Fe
- Reaction with Cold Water
- Do not react with cold/hot water; react with steam only
- Reaction with Dilute Acids
- Moderate evolution of H₂ gas
Lead, Hydrogen, Copper
- Chemical Symbol
- Pb, H, Cu
- Reaction with Cold Water
- No reaction with water or steam
- Reaction with Dilute Acids
- No reaction with dilute HCl / H₂SO₄
Silver & Gold
- Chemical Symbol
- Ag, Au
- Reaction with Cold Water
- Completely unreactive with water or steam
- Reaction with Dilute Acids
- Completely inert (dissolve only in Aqua Regia)
Formation of Ionic Bond in Sodium Chloride (NaCl)
- 1
1. Sodium atom: Na (2, 8, 1) loses 1 valence electron to attain stable neon octet: Na → Na⁺ + e⁻.
- 2
2. Chlorine atom: Cl (2, 8, 7) gains 1 electron to attain stable argon octet: Cl + e⁻ → Cl⁻.
- 3
3. Strong electrostatic electrostatic forces of attraction bind oppositely charged Na⁺ and Cl⁻ into an ionic lattice.
- 4
4. Result: Formation of solid crystalline Sodium Chloride (NaCl).
3Properties of Ionic Compounds and Metallurgy
General Characteristics of Ionic (Electrovalent) Compounds
| Characteristic | Observed Property | Underlying Molecular Reason |
|---|---|---|
| Physical Nature | Hard and brittle crystalline solids | Strong electrostatic forces of attraction between positive and negative ions |
| Melting & Boiling Points | Very high (NaCl MP = 801°C) | Tremendous amount of thermal energy required to break rigid ionic lattice |
| Solubility | Soluble in polar solvents (water); insoluble in organic solvents (petrol/kerosene) | Water molecules hydrate and pull ions apart; nonpolar solvents cannot |
| Electrical Conduction | Conducts electricity in molten state or aqueous solution; NEVER in solid state | In solid state, ions are locked in fixed lattice; in liquid/aqueous state, ions are free to drift towards electrodes |
Physical Nature
- Observed Property
- Hard and brittle crystalline solids
- Underlying Molecular Reason
- Strong electrostatic forces of attraction between positive and negative ions
Melting & Boiling Points
- Observed Property
- Very high (NaCl MP = 801°C)
- Underlying Molecular Reason
- Tremendous amount of thermal energy required to break rigid ionic lattice
Solubility
- Observed Property
- Soluble in polar solvents (water); insoluble in organic solvents (petrol/kerosene)
- Underlying Molecular Reason
- Water molecules hydrate and pull ions apart; nonpolar solvents cannot
Electrical Conduction
- Observed Property
- Conducts electricity in molten state or aqueous solution; NEVER in solid state
- Underlying Molecular Reason
- In solid state, ions are locked in fixed lattice; in liquid/aqueous state, ions are free to drift towards electrodes
4Exam Corner: Tips, Mistakes & Board Questions
Must-Know Metallurgical Terms for Exams
ClickableExam question · CBSE Class 10 Board
- A.Because electrons are absent in solids
- B.Because in solid state ions are tightly bound in fixed positions; in liquid/aqueous state ions become free to move
- C.Because solids are insulators
- D.Because ionic compounds undergo covalent bonding in water
- Conduction of electricity requires mobile charge carriers.
- In solid crystals, strong electrostatic forces keep ions fixed in lattice sites without freedom to move.
- In molten state or water solution, the crystal breaks down and ions can freely migrate to opposite electrodes.
- Correct answer is option B.
Answer: B. Because in solid state ions are tightly bound in fixed positions; in liquid/aqueous state ions become free to move
Remember
- Metals are electropositive (lose electrons); Non-metals are electronegative (gain electrons).
- TheReactivity Seriesranks metals: K > Na > Ca > Mg > Al > Zn > Fe > Pb > H > Cu > Ag > Au.
- Ionic compounds havehigh melting pointsand conduct electricity inmolten or dissolvedstate.
- Roastingheats sulphide ores in air;Calcinationheats carbonate ores without air.
Check yourself
Question 1
Which of the following metals is protected from corrosion by an unreactive self-healing oxide layer?