Metals And Nonmetals — Concepts, Reactions & Solved Examples

What Are Metals and Nonmetals?

Look at the spoon you use to eat. The wire carrying electricity to your fan. The iron rod in a construction site. All of these are metals — and understanding why they behave the way they do is one of the most scoring topics in Class 8 and Class 10 chemistry.

Metals are elements that typically have a shiny appearance, conduct heat and electricity, and can be beaten into sheets or drawn into wires. Nonmetals are elements that generally lack these properties — they tend to be dull, poor conductors, and brittle in solid state.

But chemistry never settles for “generally.” The real marks come from knowing the exceptions and the why behind each property.

We have 118 known elements. About 90 of them are metals, roughly 17 are nonmetals, and a handful sit in between (we call those metalloids). In your CBSE exam, the focus is on the physical and chemical properties of metals, their reactions with oxygen, water, and acids, and the reactivity series.

Key Terms & Definitions

Malleability — The property of a metal to be hammered into thin sheets without breaking. Gold and silver are the most malleable metals. This is why gold leaf (used in sweets!) is possible.

Ductility — The ability to be drawn into thin wires. Copper and aluminum wires in electrical cables? That’s ductility at work. Gold is the most ductile metal — 1 gram of gold can be drawn into 2 km of wire.

Conductivity — Metals conduct heat and electricity because of the free electrons in their structure. Silver is the best conductor of electricity, followed by copper — which is why most wiring uses copper (silver is too expensive).

Sonority — Metals produce a ringing sound when struck. School bells, temple bells — all metal. Nonmetals are non-sonorous.

Lustrous — Metals have a shiny surface. This is why we use them in jewellery and mirrors.

Corrosion — When metals react with substances in their environment (oxygen, water, acids) over time, they deteriorate. Rusting of iron is the classic example: $4Fe + 3O_2 + xH_2O \rightarrow 2Fe_2O_3 \cdot xH_2O$

Alloy — A mixture of a metal with one or more other metals or nonmetals. Brass = copper + zinc. Bronze = copper + tin. Steel = iron + carbon. Alloys are made to improve properties like strength, corrosion resistance, or appearance.

Reactivity Series — A list of metals arranged in decreasing order of their reactivity. This is one of the highest-weightage concepts in Class 10 — almost guaranteed to appear in board exams.

Physical Properties: Metals vs Nonmetals

Property	Metals	Nonmetals
Appearance	Lustrous (shiny)	Dull (except iodine)
State at room temperature	Mostly solid	Solid, liquid (Br), or gas
Malleability	Yes	No (brittle if solid)
Ductility	Yes	No
Conductivity (heat & electricity)	Good	Poor (except graphite)
Sonority	Yes	No
Density	Generally high	Generally low
Melting/Boiling point	Generally high	Generally low

Exception alert: Mercury is a metal that is liquid at room temperature. Gallium melts at just 29.7°C — it melts in your hand! Sodium and potassium are metals so soft you can cut them with a knife. Don’t let “metals are hard solids” become an absolute rule in your head.

Another exception: Graphite (a form of carbon, a nonmetal) conducts electricity. Iodine (a nonmetal) has a shiny appearance. These come up in objective questions to trip students.

Chemical Properties of Metals

Reaction with Oxygen

Most metals react with oxygen to form metal oxides. The general equation:

2Mg + O_2 \xrightarrow{\Delta} 2MgO

4Na + O_2 \rightarrow 2Na_2O

4Al + 3O_2 \rightarrow 2Al_2O_3

Metal oxides are basic in nature. When dissolved in water, they form alkaline solutions. This is a Class 8 board exam favourite.

Na_2O + H_2O \rightarrow 2NaOH

Amphoteric oxides — Some metal oxides like aluminium oxide ( $Al_2O_3$ ) and zinc oxide ( $ZnO$ ) react with both acids and bases. These are called amphoteric oxides and are a common Class 10 question.

Al_2O_3 + 6HCl \rightarrow 2AlCl_3 + 3H_2O \quad \text{(acting as base)}

Al_2O_3 + 2NaOH \rightarrow 2NaAlO_2 + H_2O \quad \text{(acting as acid)}

Reaction with Water

Different metals react very differently with water — and the reactivity series explains this beautifully.

Metal	Reaction with Water
Potassium (K)	Reacts violently with cold water
Sodium (Na)	Reacts vigorously with cold water
Calcium (Ca)	Reacts slowly with cold water
Magnesium (Mg)	Reacts only with steam
Aluminium (Al)	Reacts with steam (slow)
Zinc (Zn)	Reacts with steam
Iron (Fe)	Reacts with steam only
Copper, Silver, Gold	No reaction with water

2K + 2H_2O \rightarrow 2KOH + H_2\uparrow \quad \text{(violent, catches fire)}

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

Ca + 2H_2O \rightarrow Ca(OH)_2 + H_2\uparrow

Mg + H_2O \xrightarrow{\text{steam}} MgO + H_2\uparrow

3Fe + 4H_2O \xrightarrow{\text{steam}} Fe_3O_4 + 4H_2\uparrow

The iron-steam reaction producing $Fe_3O_4$ (not $Fe_2O_3$ ) is a common 1-mark question in Class 10 boards. Write it correctly — many students write $Fe_2O_3$ here and lose the mark.

Reaction with Dilute Acids

Metals above hydrogen in the reactivity series displace hydrogen from dilute acids. This is why active metals like zinc and iron react with HCl or $H_2SO_4$ , but copper and silver don’t.

Zn + H_2SO_4 \rightarrow ZnSO_4 + H_2\uparrow

Fe + 2HCl \rightarrow FeCl_2 + H_2\uparrow

Cu + H_2SO_4 \rightarrow \text{No reaction}

Why doesn’t copper react with dilute $H_2SO_4$ ? Because copper sits below hydrogen in the reactivity series — it cannot displace hydrogen from the acid. Copper does react with concentrated $HNO_3$ , but that’s a Class 11 topic.

Reaction with Salt Solutions (Displacement Reactions)

A more reactive metal displaces a less reactive metal from its salt solution. This is the basis of the activity series and appears in every board exam.

CuSO_4 + Fe \rightarrow FeSO_4 + Cu

AgNO_3 + Cu \rightarrow Cu(NO_3)_2 + 2Ag

The iron turns copper-coloured, the solution turns from blue to light green — this is a classic lab observation question.

Chemical Properties of Nonmetals

Nonmetals react with oxygen to form acidic oxides (or sometimes neutral oxides).

C + O_2 \rightarrow CO_2 \quad \text{(acidic oxide)}

S + O_2 \rightarrow SO_2 \quad \text{(acidic oxide)}

CO_2 + H_2O \rightarrow H_2CO_3 \quad \text{(carbonic acid)}

Nonmetals do not react with acids. They may react with bases (like chlorine reacts with NaOH — bleaching powder chemistry).

Nonmetal oxides are acidic. This is the rule — metal oxides are basic, nonmetal oxides are acidic. Neutralisation between the two is an important concept.

$CaO + CO_2 \rightarrow CaCO_3 \quad \text{(basic + acidic oxide }\to\text{ salt)}$

The Reactivity Series

This is the backbone of Class 10 metals chapter. Memorise it.

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

Mnemonic: “Potassium Nana Can Make A Zinc Fence, Please Help Children Have A Great Personality” (K, Na, Ca, Mg, Al, Zn, Fe, Pb, H, Cu, Hg, Ag, Au, Pt)

The reactivity series helps us predict:

Which metals react with cold water, steam, or not at all
Which metals displace others from salt solutions
Which metals can be extracted easily vs need reduction/electrolysis

This mnemonic has appeared as a memory-based question in CBSE boards. Also: metals above hydrogen react with dilute acids, metals below do not. Hydrogen’s position in the series acts as a dividing line.

Extraction of Metals

Class 10 adds an important layer — how we get pure metals from their ores depends on where they sit in the reactivity series.

Reactivity	Examples	Extraction Method
High reactivity	K, Na, Ca, Mg, Al	Electrolytic reduction
Medium reactivity	Zn, Fe, Pb, Cu	Reduction with carbon (coke) in blast furnace
Low reactivity	Hg, Ag, Au	Heating alone (thermal reduction) or found free

Fe_2O_3 + 3CO \xrightarrow{\text{blast furnace}} 2Fe + 3CO_2

2HgO \xrightarrow{\Delta} 2Hg + O_2

Solved Examples

Example 1 — Easy (CBSE Class 8)

Q: A student observes that when iron filings are added to copper sulphate solution, the blue colour fades. Explain why.

Solution: Iron is more reactive than copper (higher in the reactivity series). So iron displaces copper from copper sulphate solution:

Fe + CuSO_4 \rightarrow FeSO_4 + Cu

Iron sulphate ( $FeSO_4$ ) is light green, while copper sulphate is blue — so the blue colour fades. The copper deposits as a reddish-brown layer on the iron.

Example 2 — Medium (CBSE Class 10)

Q: An element X reacts with oxygen to form a basic oxide, reacts with dilute HCl to produce a gas, but does not react with cold water. Identify the likely position of X in the reactivity series and name one such element.

Solution:

Basic oxide → X is a metal
Reacts with dilute HCl → X is above hydrogen in reactivity series
Does not react with cold water → X is below calcium

This places X in the middle region: Al, Zn, or Fe. Zinc (Zn) is the classic answer here.

Zn + 2HCl \rightarrow ZnCl_2 + H_2\uparrow

2Zn + O_2 \rightarrow 2ZnO \quad \text{(basic oxide)}

Example 3 — Hard (CBSE Class 10 / Board Exam Pattern)

Q: Aluminium is a reactive metal yet it is widely used to make cooking utensils. Give reason. Also write the reaction of aluminium with dilute NaOH solution.

Solution: Aluminium is reactive, but it forms a thin, tough layer of aluminium oxide ( $Al_2O_3$ ) on its surface when exposed to air. This oxide layer acts as a protective coating — it prevents further reaction of the inner aluminium with oxygen, water, or acids.

This passive protection is why aluminium utensils don’t corrode easily, even though aluminium sits high in the reactivity series.

Aluminium with NaOH (amphoteric nature):

2Al + 2NaOH + 2H_2O \rightarrow 2NaAlO_2 + 3H_2\uparrow

This 3-mark question pattern — “reactive metal, yet used widely” — has appeared in CBSE Board 2023 and 2022. Always mention: (1) oxide layer forms, (2) it’s protective/passive, (3) prevents further corrosion.

Exam-Specific Tips

CBSE Class 8

Physical properties (malleability, ductility, conductivity) are tested as match-the-column or true/false in SA1.
Know the exceptions: mercury (liquid metal), graphite (conducting nonmetal), iodine (lustrous nonmetal).
3-mark questions on “properties of metals and nonmetals” — list 3 physical + 3 chemical differences.

CBSE Class 10

The reactivity series is mandatory for 3-mark and 5-mark questions.
Extraction of metals based on reactivity — this has 2-mark MCQs and 3-mark descriptive questions.
Corrosion (rusting of iron) — causes, conditions, prevention methods — appears every year.
Amphoteric oxides (Al, Zn) are high-weightage — know both reactions (with acid and base).

In CBSE Class 10 Board exams, the chapter “Metals and Non-metals” typically carries 8-10 marks. The split is usually: 1-2 MCQs (2 marks), 1 two-mark question, 1-2 three-mark questions. Reactivity series + displacement reactions + corrosion = your core scoring area.

Common Mistakes to Avoid

Mistake 1: Writing $Fe_2O_3$ for iron-steam reaction. The iron-steam reaction gives $Fe_3O_4$ (iron(II,III) oxide, also called magnetic iron oxide), not $Fe_2O_3$ . Many students write the rust formula here. These are different compounds.

Mistake 2: Saying all metal oxides dissolve in water. Not all metal oxides dissolve — $Al_2O_3$ , $Fe_2O_3$ , $CuO$ are insoluble in water. Only oxides of highly reactive metals (Na, K, Ca) dissolve freely. Don’t write “metal oxide + water → alkali” as a universal rule.

Mistake 3: Forgetting the conditions in extraction equations. $Fe_2O_3$ reduced in blast furnace uses CO as the reducing agent, not coke directly in many reactions. Write the correct reducing agent and conditions — examiners check this.

Mistake 4: Confusing displacement with double displacement. $Fe + CuSO_4 \rightarrow FeSO_4 + Cu$ is a single displacement (one metal pushes out another). $NaCl + AgNO_3 \rightarrow AgCl + NaNO_3$ is double displacement (both ionic partners swap). Don’t mix these two reaction types.

Mistake 5: Thinking nonmetals never conduct electricity. Graphite (carbon, a nonmetal) conducts electricity — this is explicitly mentioned in NCERT Class 8. If an MCQ says “all nonmetals are poor conductors” — that’s false. Graphite is the exception.

Practice Questions

Q1. Name the property of metals due to which they can be beaten into thin sheets. Name one metal that is an exception to this property.

Malleability. Exception: Zinc is brittle at room temperature (though it becomes malleable on heating). Also accept: sodium and potassium are soft metals. The question usually expects you to say “zinc is brittle.”

Q2. Arrange the following metals in decreasing order of reactivity: Cu, Zn, Fe, Na, Al

Na > Al > Zn > Fe > Cu

(From the reactivity series: K > Na > Ca > Mg > Al > Zn > Fe > Pb > H > Cu)

Q3. When copper is heated in air, it forms a black coating. Write the balanced equation and identify the type of reaction.

2Cu + O_2 \xrightarrow{\Delta} 2CuO

CuO is black copper(II) oxide. This is a combination reaction (two reactants combine to form one product) and also an oxidation reaction (copper is oxidised).

Q4. A metal M does not react with cold water, reacts slowly with hot water, and vigorously with steam. Identify M and write its reaction with steam.

M is Magnesium (Mg).

Mg + H_2O \xrightarrow{\text{steam}} MgO + H_2\uparrow

Magnesium reacts slowly with hot water and vigorously with steam. It does not react with cold water (unlike Na and K).

Q5. Why is sodium stored under kerosene?

Sodium is highly reactive — it reacts vigorously with both air (oxygen) and water moisture:

4Na + O_2 \rightarrow 2Na_2O

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

The hydrogen produced can catch fire. Kerosene is a non-aqueous, non-reactive liquid that covers the sodium surface, preventing contact with air and moisture.

Q6. What is an amphoteric oxide? Give two examples with equations.

An amphoteric oxide reacts with both acids and bases to form salt and water.

Examples: Aluminium oxide ( $Al_2O_3$ ) and Zinc oxide (ZnO)

With acid:

Al_2O_3 + 6HCl \rightarrow 2AlCl_3 + 3H_2O

With base:

Al_2O_3 + 2NaOH \rightarrow 2NaAlO_2 + H_2O

For ZnO:

ZnO + H_2SO_4 \rightarrow ZnSO_4 + H_2O

ZnO + 2NaOH \rightarrow Na_2ZnO_2 + H_2O

Q7. Silver articles turn black over time. Explain with a chemical equation.

Silver reacts slowly with hydrogen sulphide ( $H_2S$ ) present in the air to form silver sulphide ( $Ag_2S$ ), which is black. This is called tarnishing (a form of corrosion).

4Ag + 2H_2S + O_2 \rightarrow 2Ag_2S + 2H_2O

(Class 10 boards sometimes accept the simpler: $2Ag + H_2S \rightarrow Ag_2S + H_2$ )

Q8. Explain why copper is used in electrical wiring but iron is not, even though iron is more abundant and cheaper.

Copper is used because:

Copper has very high electrical conductivity (second only to silver among practical metals).
Copper is ductile — it can be drawn into thin wires easily.
Copper is resistant to corrosion — iron rusts rapidly, which would increase resistance and cause failures.
Copper does not react with moisture in air under normal conditions.

Iron, despite being cheaper, corrodes rapidly (rusting), which degrades conductivity and structural integrity of wires.

FAQs

What is the difference between metals and nonmetals? Metals are lustrous, malleable, ductile, and good conductors of heat and electricity. Nonmetals are dull, brittle (in solid state), and poor conductors (except graphite). Metals form basic oxides; nonmetals form acidic oxides.

Which metal is the best conductor of electricity? Silver is the best conductor of electricity. But copper is used in electrical wiring because it’s far cheaper and nearly as conductive. Aluminium is used in high-tension transmission wires because of its low density.

Why does aluminium not corrode despite being reactive? Aluminium rapidly forms a thin, tightly adherent layer of $Al_2O_3$ on its surface when exposed to air. This oxide layer is impermeable — it blocks further oxygen from reaching the underlying aluminium. This is called passivation.

Is hydrogen a metal or nonmetal? Hydrogen is a nonmetal. It’s placed in Group 1 of the periodic table alongside alkali metals only because it has 1 valence electron, but its properties are closer to nonmetals. It’s a gas, forms $H^+$ ions (like metals), but also $H^-$ (hydride) ions — it’s genuinely unique.

What is the difference between corrosion and rusting? Rusting is specifically the corrosion of iron to form hydrated iron(III) oxide ( $Fe_2O_3 \cdot xH_2O$ ). Corrosion is the general term for any metal degrading due to environmental reactions. All rusting is corrosion, but not all corrosion is rusting.

Which nonmetal conducts electricity? Graphite (an allotrope of carbon) conducts electricity due to the presence of delocalised electrons in its layered structure. This is the only nonmetal that conducts electricity and is tested frequently in MCQs.

How do we prevent rusting? Rusting requires both oxygen and water. Prevention methods: painting or coating (blocks contact), galvanisation (zinc coating — zinc corrodes sacrificially instead of iron), alloying (stainless steel = iron + chromium + nickel), oiling/greasing, and electroplating.

What is the reactivity series used for? The reactivity series predicts: (1) which metals react with water/steam/acid, (2) which metals displace others from salt solutions, (3) which extraction method to use for a metal. It’s the single most useful tool in the metals chapter for solving problems.