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REET Level 2 · Science

Metals and Non-Metals — REET Level 2 Science Notes

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This page covers metals and non-metals for REET Level 2 Science — a comparison of their physical properties, the exceptions, and the acidic-basic-amphoteric classification of oxides — in exam-focused form. REET 2024 asked a direct question on amphoteric oxides (Al₂O₃).

  • 1 question in REET 2024
  • Class 6-8 level content
  • 6 min read
Verified 17 September 2026

How REET actually asks this topic

REET 2024 asked you to directly identify an amphoteric oxide (Al₂O₃). In other words, alongside the physical properties of metals and non-metals, REET also asks fine-grained questions on the acidic, basic, and amphoteric classification of oxides, so it's important to understand this distinction clearly.

Identifying metals and non-metals

Elements are divided into metals and non-metals based on their physical and chemical properties. Most elements are metals (such as iron, copper, aluminium), while non-metals are comparatively fewer in number (such as carbon, oxygen, sulphur, iodine).

Metals and non-metals are never identified from a single property alone — several physical and chemical properties are looked at together, because almost every rule here comes with a few exceptions. This is exactly why exams like REET so often build questions around these exceptions.

In everyday life, metals are used for utensils, wires, jewellery, vehicles, and construction, while non-metals are used for things like fuel (coal), fertilisers (nitrogen, phosphorus), and medicine (iodine tincture).

Comparing the physical properties of metals and non-metals

Metals

MalleabilityCan be hammered into thin sheets

DuctilityCan be drawn into wires

SonorousnessMakes a ringing sound when struck

ConductivityGood conductor of heat and electricity

LustreGenerally shiny

State at room temperatureMostly solid (exception: mercury — liquid)

Non-metals

MalleabilityGenerally brittle, does not form sheets

DuctilityCannot be drawn into wire (brittle)

SonorousnessDoes not produce sound

ConductivityGenerally a poor conductor (exception: graphite is a good conductor)

LustreGenerally dull (exception: iodine is lustrous)

State at room temperatureFound in all three states — solid, liquid (bromine), and gas

REET keeps coming back to exception cases — mercury, graphite, iodine — so these are worth specifically highlighting and remembering.

Exceptions worth remembering

Mercury
The only common metal that is liquid at room temperature; used in traditional thermometers
Graphite
A non-metal that is nonetheless a good conductor of electricity, which is why it's used in pencil lead and electrical electrodes
Iodine
A non-metal that is nonetheless lustrous; used as an antiseptic in medicine
Bromine
A non-metal that is liquid at room temperature, dark reddish-brown in colour, and has a sharp smell
Diamond
A form of carbon, extremely hard yet (unlike graphite) a poor conductor of electricity; used in jewellery and in industrial cutting and drilling tools

Everyday uses of metals and non-metals

SubstanceMain use
IronTools, machinery, construction rebar
CopperElectrical wire, utensils (because of its conductivity)
AluminiumUtensils, aircraft bodies (because it is light and strong)
CarbonFuel (coal), and as graphite in pencil lead
Oxygen and nitrogenRespiration and the fertiliser industry
IodineAs an antiseptic in medicine (tincture of iodine)

These uses also make it clear that both metals and non-metals are indispensable in everyday life — only their fields of application differ. Which substance to choose is decided by looking at its specific property, such as conductivity, lightness, or reactivity.

Oxides of metals and non-metals — acidic, basic and amphoteric

Metal oxides are generally basic, such as Na₂O and CaO — these dissolve in water to form a base. Non-metal oxides are generally acidic, such as CO₂ — these dissolve in water to form an acid.

Some metal oxides react with both acids and bases to form salt and water; these are called amphoteric oxides — such as aluminium oxide (Al₂O₃) and zinc oxide (ZnO). Whether an oxide is acidic, basic or amphoteric helps decide whether an element is fundamentally a metal or a non-metal.

Metals generally react with dilute acids (such as dilute HCl) to release hydrogen gas and form the corresponding salt, whereas non-metals generally do not react with acids this way. This is exactly why chemical behaviour, alongside physical properties, is used to identify metals and non-metals.

The reactivity of metals also differs — metals like sodium and potassium react very quickly with water and air, while metals like gold and silver are far less reactive, which is exactly why they are used in jewellery: they do not corrode easily.

How to teach this to children

Classroom activity

Take turns lightly hammering a copper wire, aluminium foil, a carbon rod (pencil lead) and a piece of sulphur, and compare their malleability. Record the results in a table as 'formed a sheet / did not form a sheet'.

Teaching aids

Show a chart of everyday examples of metals and non-metals (utensils-wires versus coal-sulphur) with pictures, and mark exceptions like mercury and graphite in a different colour. If possible, showing a mercury thermometer reinforces the idea of a liquid metal.

Common misconception

Students often assume all non-metals are poor conductors and all metals are solid; correct this using the examples of graphite (a conducting non-metal) and mercury (a liquid metal). It's also worth clarifying that lustre alone doesn't determine whether something is a metal or a non-metal, since a non-metal like iodine can be lustrous too.

Assessment idea

Give students names of different substances and have them classify each as a metal or a non-metal and explain their reasoning — this checks their practical understanding of the properties. You can also ask them what test they would use to classify an oxide as acidic, basic, or amphoteric.

Memory trick

To remember amphoteric oxides, remember 'AZ' — Aluminium (Al₂O₃) and Zinc (ZnO) — both of their oxides are amphoteric, meaning they react with both acids and bases. For the exceptions, remember — 'mercury is liquid, graphite conducts, iodine is shiny' — these three make up the most common chain of exceptions to the rule.

REET 2024 question (with solution)

Question 150

Example of amphoteric oxide is

  1. ANa₂O
  2. BCO₂
  3. CAl₂O₃
  4. DCaO

Explanation

उभयधर्मी ऑक्साइड वे हैं जो अम्ल और क्षार दोनों से अभिक्रिया करके लवण और जल बनाते हैं। Al₂O₃ HCl और NaOH दोनों से अभिक्रिया करता है, इसलिए उभयधर्मी है। Na₂O और CaO क्षारकीय ऑक्साइड हैं तथा CO₂ अम्लीय ऑक्साइड है।

Practice questions

Question 1

Which of the following metals exists in a liquid state at room temperature?

  1. Aलोहा
  2. Bतांबा
  3. Cपारा (मरकरी)
  4. Dएल्युमिनियम

Explanation

Mercury is the only common metal found in a liquid state at room temperature; all the other options are solid metals.

Question 2

Which of the following non-metals is a good conductor of electricity?

  1. Aगंधक
  2. Bग्रेफाइट
  3. Cआयोडीन
  4. Dफॉस्फोरस

Explanation

Graphite is a non-metal that is nonetheless a good conductor of electricity — an exception to the general rule for non-metals.

Question 3

An amphoteric oxide is one that

  1. Aकेवल अम्ल से अभिक्रिया करता है
  2. Bकेवल क्षार से अभिक्रिया करता है
  3. Cअम्ल व क्षार दोनों से अभिक्रिया करके लवण व जल बनाता है
  4. Dकिसी से भी अभिक्रिया नहीं करता

Explanation

That is exactly the definition of an amphoteric oxide — it reacts with both acids and bases to form salt and water.

Question 4

Which of the following is an amphoteric oxide?

  1. ANa₂O
  2. BCaO
  3. CAl₂O₃
  4. DCO₂

Explanation

Al₂O₃ (aluminium oxide) reacts with both acids and bases, which makes it amphoteric. Na₂O and CaO are basic oxides, and CO₂ is an acidic oxide.

Question 5

Oxides of metals are generally

  1. Aअम्लीय
  2. Bक्षारकीय
  3. Cउदासीन
  4. Dउभयधर्मी

Explanation

Metal oxides are generally basic, such as Na₂O and CaO, which dissolve in water to form a base.

Question 6

Oxides of non-metals are generally

  1. Aअम्लीय
  2. Bक्षारकीय
  3. Cउदासीन
  4. Dउभयधर्मी

Explanation

Non-metal oxides are generally acidic, such as CO₂, which dissolves in water to form an acid.

Question 7

Which of the following properties is NOT a general property of non-metals?

  1. Aभंगुर होना
  2. Bकुचालक होना
  3. Cआघातवर्ध्य (malleable) होना
  4. Dचमकरहित होना

Explanation

Non-metals are generally brittle and not malleable (they don't form sheets when hammered); malleability is a property of metals.

Question 8

To directly show children the difference in malleability, a teacher would choose which activity as most suitable?

  1. Aकेवल परिभाषा बताना
  2. Bधातु व अधातु के टुकड़ों को हल्के हथौड़े से ठोककर परिणाम की तुलना कराना
  3. Cचित्र दिखाना
  4. Dकोई प्रयोग न कराना

Explanation

A direct experiment lets children see for themselves that a metal flattens when hammered while a non-metal breaks, which makes the difference in malleability clear.

Question 9

Which of the following pairs is NOT correctly matched?

  1. Aग्रेफाइट - अधातु परन्तु विद्युत चालक
  2. Bपारा - धातु परन्तु द्रव अवस्था
  3. Cआयोडीन - अधातु परन्तु चमकदार
  4. Dसोडियम - अधातु परन्तु ठोस

Explanation

Sodium is a metal, not a non-metal; the other three pairs — graphite, mercury, iodine — are all correct exceptions within their respective groups.

Question 10

Students commonly have the misconception that all metals are shiny and solid. Which example would a teacher give to best correct this?

  1. Aसोना व चांदी
  2. Bपारा (द्रव धातु) का उदाहरण
  3. Cलोहा
  4. Dतांबा

Explanation

Mercury, a metal that stays liquid at room temperature, is the best example for correcting the misconception that all metals are shiny and solid.

Frequently asked questions

What is an amphoteric oxide?+

A metal oxide that reacts with both acids and bases to form salt and water is called an amphoteric oxide; examples include Al₂O₃ and ZnO.

Which non-metal conducts electricity?+

Graphite is a non-metal that is nonetheless a good conductor of electricity — this is an exception to the general rule for non-metals, which is why it's used in pencil lead as well as in electrical circuits.

Which metal is liquid at room temperature?+

Mercury is the only common metal found in a liquid state at room temperature, and it was used in traditional thermometers.

What's the difference between metal oxides and non-metal oxides?+

Metal oxides are generally basic, while non-metal oxides are generally acidic; some metal oxides (such as Al₂O₃) are also amphoteric.

How does REET ask questions on metals and non-metals?+

Around exceptions to physical properties (such as mercury and graphite) and around the classification of oxides (acidic/basic/amphoteric), as seen in the REET 2024 question.

What do metals form when they react with acid?+

Most metals react with dilute acid to release hydrogen gas and form the corresponding salt; non-metals generally don't react with acids this way.

Why are gold and silver used in jewellery?+

Gold and silver are both very unreactive metals that don't corrode easily from air or moisture, so their shine lasts a long time.

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Change Log

  • 17 September 2026 — English page published — mirrors the fact-checked Hindi page, independently bilingual-accuracy checked