ScienceCBSE Class 10 · Metals and Non-metals

Chemical Properties of Metals

Updated 14 October 2026 · Fact-checked

Metals react with oxygen to form metal oxides, with water to give a metal oxide or hydroxide and hydrogen, with dilute acids to give a salt and hydrogen, and with salt solutions of less reactive metals by displacing them. How vigorously each reacts depends on its place in the reactivity series.

Understand Chemical Properties of Metals

All metals tend to lose electrons, but some do it far more readily than others. The four reactions below are how we compare them, and together they build the reactivity series.

1. With oxygen: metal + oxygen → metal oxide. Copper heated in air gets a black coat of copper(II) oxide, $2 C u + O_{2} \to 2 C u O$ ; aluminium forms aluminium oxide, $4 A l + 3 O_{2} \to 2 A l_{2} O_{3}$ . Metal oxides are generally basic. A few, such as aluminium oxide and zinc oxide, react with both acids and bases to give salt and water; they are amphoteric oxides: $A l_{2} O_{3} + 6 H C l \to 2 A l C l_{3} + 3 H_{2} O$ and $A l_{2} O_{3} + 2 N a O H \to 2 N a A l O_{2} + H_{2} O$ (sodium aluminate). Most metal oxides do not dissolve in water, but sodium and potassium oxides dissolve to form alkalis, $N a_{2} O + H_{2} O \to 2 N a O H$ . Metals differ greatly: potassium and sodium catch fire in the open, so they are stored under kerosene; magnesium, aluminium, zinc and lead get a thin protective oxide layer at room temperature; iron filings burn only when sprinkled into a flame; copper does not burn but blackens; silver and gold do not react with oxygen even when strongly heated.

2. With water: metal + water → metal oxide + hydrogen; a soluble oxide then gives the hydroxide. Potassium and sodium react violently with cold water and the hydrogen catches fire. Calcium reacts less violently; the heat is not enough to ignite the hydrogen, and calcium floats because hydrogen bubbles stick to it. Magnesium does not react with cold water but does with hot water, and also floats. Aluminium, iron and zinc react only with steam, giving the oxide: $3 F e + 4 H_{2} O \to F e_{3} O_{4} + 4 H_{2}$ . Lead, copper, silver and gold do not react with water at all.

3. With dilute acids: metal + dilute acid → salt + hydrogen. With dilute hydrochloric acid the rate of bubbling and the rise in temperature fall in the order Mg > Al > Zn > Fe, and copper shows no reaction. Metals above hydrogen in the series can displace hydrogen from dilute acids; those below cannot. Nitric acid is an exception: it is a strong oxidising agent that turns the hydrogen into water, except with magnesium and manganese in very dilute nitric acid.

4. With salt solutions: a more reactive metal displaces a less reactive one. An iron nail in copper sulphate solution gets a brown coat of copper and the blue colour fades, but a copper wire in iron sulphate solution shows no change. So iron is more reactive than copper. Displacement gives the clearest evidence of reactivity, which is how the series K > Na > Ca > Mg > Al > Zn > Fe > Pb > [H] > Cu > Hg > Ag > Au was built.

Board questions ask you to write equations, explain observations (floating calcium, storing sodium in kerosene), use a results table to rank unknown metals, or predict whether a displacement will occur.

Chemical Properties of Metals: formulas and key facts

Metal + oxygen: $4 A l + 3 O_{2} \to 2 A l_{2} O_{3}$; Also $2 C u + O_{2} \to 2 C u O$ (black).
Amphoteric oxide: $A l_{2} O_{3} + 2 N a O H \to 2 N a A l O_{2} + H_{2} O$; With acid: $A l_{2} O_{3} + 6 H C l \to 2 A l C l_{3} + 3 H_{2} O$ . ZnO behaves alike.
Metal + cold water: $2 N a + 2 H_{2} O \to 2 N a O H + H_{2}$; Violent, exothermic; hydrogen catches fire. Calcium: $C a + 2 H_{2} O \to C a (O H)_{2} + H_{2}$ .
Metal + steam: $2 A l + 3 H_{2} O \to A l_{2} O_{3} + 3 H_{2}$; Iron: $3 F e + 4 H_{2} O \to F e_{3} O_{4} + 4 H_{2}$ . These metals give oxides, not hydroxides.
Metal + dilute acid: $F e + H_{2} S O_{4} \to F e S O_{4} + H_{2}$; Rate with dilute HCl: Mg > Al > Zn > Fe; Cu does not react.
Displacement: $F e + C u S O_{4} \to F e S O_{4} + C u$; Metal A + salt solution of B → salt solution of A + metal B, if A is above B.
Reactivity series: $K > N a > C a > M g > A l > Z n > F e > P b > [H] > C u > H g > A g > A u$; Metals above H displace hydrogen from dilute acids.

How to solve Chemical Properties of Metals questions

For questions on reactions of metals, decide the reagent first, then use the series.

1Identify the reagent: oxygen, water (cold, hot or steam), dilute acid or a salt solution.
2Locate the metal in the reactivity series and recall its behaviour with that reagent.
3Write the general word pattern, then the balanced equation. With steam, the product is the oxide; with cold or hot water, the hydroxide.
4Add the expected observation: fire, floating, bubbles, brown deposit, fading blue colour, no change.
5For displacement predictions, compare positions: a reaction happens only if the free metal is above the metal in the salt.
6For tables of unknown metals, count how many salts each metal displaces; more displacements means more reactive.

Chemical Properties of Metals in real life

Each concept, met in an everyday situation. Read the situation, try the problem, then check the solution. The one-line hook is what to remember.

Displacement and the reactivity series

Suppose your science club wants to store copper sulphate solution for a week and the only containers available are an iron bucket, an aluminium pot and a copper vessel.

Which container should be used? Predict what would happen in the other two, with equations, and explain using the reactivity series.

Try it first, then show the solutionSolution

Reactivity: Al > Fe > Cu.
Iron is above copper, so it displaces copper: $F e + C u S O_{4} \to F e S O_{4} + C u$ . The bucket would get a brown copper coating and the blue colour would fade to green.
Aluminium is above copper, so it also displaces copper: $2 A l + 3 C u S O_{4} \to A l_{2} (S O_{4})_{3} + 3 C u$ . The pot would be eaten away and the solution would lose its blue colour.
Copper cannot displace itself; no reaction occurs in the copper vessel.

Answer: Use the copper vessel. Iron and aluminium are more reactive than copper and would displace it from the solution, damaging the containers and changing the solution.

Memory hook: Store a metal's salt only in that metal or one below it in the series.

Tricks to remember Chemical Properties of Metals

Short memory aids. Say each one aloud once, then use it on a question the same day.

Reactivity series mnemonic
'Please Send Cats, Monkeys And Zebras In Large Hired Cages, Make Sure Gently' = K, Na, Ca, Mg, Al, Zn, Fe, Pb, H, Cu, Hg, Ag, Au.
Use it when: Writing the series in the right order.
Water ladder
Cold water: K, Na, Ca. Hot water: Mg. Steam: Al, Zn, Fe. None: Pb, Cu, Ag, Au.
Use it when: Reaction-with-water questions.
Floaters
Calcium and magnesium float because hydrogen bubbles cling to them.
Use it when: 'Why does calcium float?' reasoning.

Chemical Properties of Metals: solved examples

Ordered from board level to HOTS. Try each one before you open the solution.

Example 1: Reactions with water · 3 marks · Short answerBoard level

Write balanced equations for the reactions of (a) iron with steam, (b) calcium with water, (c) potassium with water. Why does potassium need to be stored under kerosene?

Try it first, then show the solutionSolution

(a) $3 F e (s) + 4 H_{2} O (g) \to F e_{3} O_{4} (s) + 4 H_{2} (g)$ (½ mark).
(b) $C a (s) + 2 H_{2} O (l) \to C a (O H)_{2} (a q) + H_{2} (g)$ (½ mark).
(c) $2 K (s) + 2 H_{2} O (l) \to 2 K O H (a q) + H_{2} (g)$ + heat (1 mark).
Potassium reacts so vigorously with oxygen and moisture that it catches fire in the open; kerosene keeps air and water away (1 mark).

Answer: (a) $3 F e + 4 H_{2} O \to F e_{3} O_{4} + 4 H_{2}$ . (b) $C a + 2 H_{2} O \to C a (O H)_{2} + H_{2}$ . (c) $2 K + 2 H_{2} O \to 2 K O H + H_{2}$ . Kerosene prevents fires.

Example 2: Amphoteric oxides · 3 marks · Short answerHarder board level

(a) What are amphoteric oxides? Name two. (b) Write equations to show the amphoteric nature of aluminium oxide. (c) Aluminium is a reactive metal, yet it is used to make cooking utensils. Explain.

Try it first, then show the solutionSolution

(a) Metal oxides that react with both acids and bases to give salt and water; aluminium oxide and zinc oxide (1 mark).
(b) $A l_{2} O_{3} + 6 H C l \to 2 A l C l_{3} + 3 H_{2} O$ and $A l_{2} O_{3} + 2 N a O H \to 2 N a A l O_{2} + H_{2} O$ (1 mark).
(c) At room temperature aluminium gets a thin layer of aluminium oxide on its surface, which protects it from further oxidation; it also conducts heat well (1 mark).

Answer: (a) Oxides reacting with acids and bases; $A l_{2} O_{3}$ , ZnO. (b) Two equations as above. (c) A protective oxide layer stops further reaction.

Example 3: Ranking unknown metals · 4 marks · Short answerHarder board level

Four metals P, Q, R and S were added to solutions as shown.
P: displaces metal from copper(II) sulphate and silver nitrate, but not from iron(II) sulphate or zinc sulphate.
Q: displaces metal from iron(II) sulphate, copper(II) sulphate and silver nitrate, but not from zinc sulphate.
R: displaces metal only from silver nitrate.
S: displaces metal from none of them.
(a) Which is the most reactive? (b) What would you see if R were placed in copper(II) sulphate? (c) Arrange P, Q, R, S in decreasing reactivity. (d) Between which two metals of the reactivity series must Q lie?

Try it first, then show the solutionSolution

(a) Q, which displaces the most metals (three) (1 mark).
(b) Nothing; R does not displace copper, so R is below copper (1 mark).
(c) Q > P > R > S (1 mark).
(d) Q displaces iron but not zinc, so Q is less reactive than zinc and more reactive than iron: it lies between Zn and Fe (1 mark).

Answer: (a) Q. (b) No change. (c) Q > P > R > S. (d) Between zinc and iron.

Example 4: Metals and dilute acids · 5 marks · Long answerHarder board level

Magnesium, aluminium, zinc, iron and copper are added to separate test tubes of dilute hydrochloric acid with a thermometer in each. (a) Arrange them in decreasing order of reactivity from the expected observations. (b) In which tube is the highest temperature recorded? (c) Write the equation for zinc. (d) Why does no hydrogen come off if dilute nitric acid is used with zinc?

Try it first, then show the solutionSolution

(a) Mg > Al > Zn > Fe; copper shows no reaction (bubble rate and temperature rise) (1½ marks).
(b) The magnesium tube: its reaction is fastest and most exothermic (1 mark).
(c) $Z n (s) + 2 H C l (a q) \to Z n C l_{2} (a q) + H_{2} (g)$ (1 mark).
(d) Nitric acid is a strong oxidising agent; it oxidises the hydrogen formed to water and is itself reduced to oxides of nitrogen (only magnesium and manganese give hydrogen, with very dilute nitric acid) (1½ marks).

Answer: (a) Mg > Al > Zn > Fe, Cu no reaction. (b) Magnesium. (c) $Z n + 2 H C l \to Z n C l_{2} + H_{2}$ . (d) $H N O_{3}$ oxidises $H_{2}$ to water.

Example 5: Galvanised iron in a salt solution · 3 marks · Short answerHOTS / competency

A student dips a strip of zinc into iron(II) sulphate solution and a strip of iron into zinc sulphate solution. (a) In which case does a reaction occur? Write the equation and one observation. (b) Use this result to explain why zinc is a better coating than tin for protecting iron from rusting, but tin is used for food cans. (Tin lies below iron and zinc in reactivity.)

Try it first, then show the solutionSolution

(a) Zinc in iron(II) sulphate: $Z n + F e S O_{4} \to Z n S O_{4} + F e$ ; the pale green colour fades and a dark deposit of iron forms on the zinc (1 mark).
(b) Zinc is more reactive than iron, so even where the zinc coat is scratched, zinc reacts in preference to iron and protects it (1 mark).
(b) For food cans, a reactive coating like zinc could react with acids in food; tin is less reactive than zinc, so it does not react with the food (1 mark).

Answer: (a) Zinc displaces iron: $Z n + F e S O_{4} \to Z n S O_{4} + F e$ . (b) Zinc's higher reactivity protects iron sacrificially; for food, the less reactive tin avoids reactions with the food.

Where students lose marks in Chemical Properties of Metals

The slips examiners see most often, and what to write instead.

Mistake: Writing hydroxide for a steam reaction
Students apply the sodium pattern to all metals.
Wrong working
$F e + 2 H_{2} O \to F e (O H)_{2} + H_{2}$ with steam.
Right working
$3 F e + 4 H_{2} O \to F e_{3} O_{4} + 4 H_{2}$
Do this: Steam gives the metal oxide; only soluble oxides in water give hydroxides.
Usually costs: The equation mark.
Mistake: Predicting displacement the wrong way round
Students check whether the salt's metal is more reactive rather than the free metal.
Wrong working
Copper displaces iron from iron sulphate.
Right working
Iron displaces copper from copper sulphate; copper in iron sulphate shows no change.
Do this: Ask: is the free metal higher? If yes, displacement; if no, nothing.
Usually costs: 1 mark in MCQs and prediction questions.
Mistake: Saying all metals give hydrogen with all acids
The general pattern is over-applied.
Wrong working
Copper + dilute HCl gives copper chloride and hydrogen.
Right working
Copper does not react with dilute HCl; and nitric acid usually gives no hydrogen.
Do this: Only metals above hydrogen react; remember the nitric acid exception.
Usually costs: 1 mark.
Mistake: Unbalanced aluminium equations
Al and O need a 4 : 3 : 2 ratio that students skip.
Wrong working
$A l + O_{2} \to A l_{2} O_{3}$
Right working
$4 A l + 3 O_{2} \to 2 A l_{2} O_{3}$
Do this: Balance oxygen with the lowest common multiple of 2 and 3, then aluminium.
Usually costs: ½ mark.

Exam tips

Learn the reactivity series in order; most reasoning questions depend on it.
For water reactions, mention the condition (cold water, hot water, steam) in the answer.
For displacement questions, write both the observation (colour change, deposit) and the equation.
Use NCERT reasons: kerosene for sodium and potassium, protective oxide layer for aluminium, hydrogen bubbles for floating.
In results tables, show your counting of displacements so the examiner can follow your ranking.

Practice questions on Chemical Properties of Metals

Write each answer on paper first. Open the hint only if you are stuck, and the answer only when you have finished.

Q1 · 1 mark · MCQBoard level
Which pair will give a displacement reaction?
(a) $M g C l_{2}$ solution and aluminium (b) $A g N O_{3}$ solution and copper (c) $N a C l$ solution and copper (d) $F e S O_{4}$ solution and silver
Hint
The free metal must be above the metal in the salt.
Answer
(b). Copper is above silver: $C u + 2 A g N O_{3} \to C u (N O_{3})_{2} + 2 A g$ .
Q2 · 2 marks · Very short answerBoard level
Why does calcium start floating when it reacts with water, while sodium's reaction gives a flame? Write the equation for calcium.
Hint
Compare how much heat each reaction releases.
Answer
Hydrogen bubbles stick to the calcium surface and make it float. Calcium's reaction releases less heat than sodium's, not enough to set the hydrogen on fire. $C a + 2 H_{2} O \to C a (O H)_{2} + H_{2}$ .
Q3 · 1 mark · Assertion-reasonHarder board level
Assertion (A): Copper does not give hydrogen with dilute hydrochloric acid.
Reason (R): Copper is placed below hydrogen in the reactivity series.
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true.
Hint
Which metals can displace hydrogen from dilute acids?
Answer
(a). Only metals above hydrogen displace it from dilute acids.
Q4 · 3 marks · Short answerHOTS / competency
An element E burns in air to form an oxide with a high melting point that dissolves in water to give a solution which turns red litmus blue. E reacts with cold water, though less violently than sodium. Identify E, write the equations for its burning and for its reaction with water, and say why the hydrogen formed does not catch fire.
Hint
A metal that reacts with cold water but less violently than sodium, and floats.
Answer
E is calcium. $2 C a + O_{2} \to 2 C a O$ ; $C a + 2 H_{2} O \to C a (O H)_{2} + H_{2}$ . The reaction is less violent and the heat evolved is not enough to ignite the hydrogen.
Q5 · 4 marks · Case-basedHOTS / competency
Read the passage and answer.
Suppose a laboratory assistant finds an old jar labelled 'sodium' in which the kerosene has dried up. The metal pieces inside are covered with a white crust, and one piece dropped into a beaker of water darts about and bursts into a small yellow flame.
(a) Why is sodium normally kept under kerosene? (1 mark)
(b) Name the gas that burns in the beaker and write the balanced equation for the reaction. (1 mark)
(c) A piece of calcium dropped into water reacts steadily and starts floating, but no flame appears. Explain both differences from sodium, and say what the solution in each beaker would do to red litmus. (2 marks)
Hint
Compare how much heat the two reactions give out, and what forms in the water.
Answer
(a) Sodium reacts so vigorously with oxygen and moisture in the air that it can catch fire in the open; kerosene keeps air and water away. (b) Hydrogen: $2 N a + 2 H_{2} O \to 2 N a O H + H_{2}$ ; the reaction is so exothermic that the hydrogen catches fire. (c) Calcium reacts less violently, so the heat released is not enough to ignite the hydrogen; bubbles of hydrogen stick to the calcium and make it float. Both beakers now contain an alkali (sodium hydroxide or calcium hydroxide), so both turn red litmus blue.
Q6 · 3 marks · Short answerHarder board level
Write balanced equations for: (a) aluminium with steam, (b) magnesium with hot water, (c) sodium oxide with water. State one difference between the products of (a) and (b) and give the reason.
Hint
With steam the product is the oxide; with hot water, magnesium gives the hydroxide.
Answer
(a) $2 A l + 3 H_{2} O \to A l_{2} O_{3} + 3 H_{2}$ . (b) $M g + 2 H_{2} O \to M g (O H)_{2} + H_{2}$ . (c) $N a_{2} O + H_{2} O \to 2 N a O H$ . Difference: aluminium reacts only with steam and gives its oxide, while magnesium reacts with hot water and gives its hydroxide. Aluminium does not react with cold or hot water at all, so it needs steam, and in steam the metal oxide is the product.

Test your recall

Answer in your head or on paper first, then open the card. Pulling an answer out of memory makes it stick far better than re-reading.

1.Name two amphoteric oxides.Show answer
Aluminium oxide and zinc oxide.
2.Which metals react only with steam?Show answer
Aluminium, iron and zinc.
3.Order of reactivity with dilute HCl from NCERT?Show answer
Mg > Al > Zn > Fe; copper does not react.
4.Why is nitric acid special with metals?Show answer
It is a strong oxidising agent and oxidises the hydrogen to water, so usually no hydrogen is released.
5.Which metals do not react with oxygen even at high temperatures?Show answer
Silver and gold.
6.What happens to an iron nail in copper sulphate solution?Show answer
It gets a brown copper coating and the blue colour fades.

Chemical Properties of Metals: frequently asked questions

What are the four main chemical properties of metals in Class 10?

Reaction with oxygen (oxides), with water (oxides or hydroxides and hydrogen), with dilute acids (salt and hydrogen) and with salt solutions of less reactive metals (displacement).

Why is sodium stored in kerosene?

Sodium reacts so vigorously with oxygen and moisture that it can catch fire in the open. Kerosene keeps it away from air and water.

What is the reactivity series?

A list of metals arranged in decreasing order of reactivity: K, Na, Ca, Mg, Al, Zn, Fe, Pb, [H], Cu, Hg, Ag, Au.

Why doesn't copper react with dilute hydrochloric acid?

Copper is below hydrogen in the reactivity series, so it cannot displace hydrogen from the acid.

Do metals always give basic oxides?

Most do, but aluminium oxide and zinc oxide are amphoteric: they react with both acids and bases.