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Physical properties of non-metals - class-VIII

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Match List - I (Position of the Metal in the Activity Series) with the List - II (Related Reduction Process) and select the correct option using the codes given below.

List - I(Position of the Metal in the Activity Series) List - II(Related Reduction Process)
(A) The bottom of the series (I) Electrolysis
(B) The top of the series (II) Reduction by heat alone
(C) The lower regions of the series (III) Found in native state
(D) The middle of the series (IV) Reduction using carbon or some other reducing agent
  1. $A - II, B - III, C - IV, D - I$

  2. $A - II, B - I, C - IV, D - III$

  3. $A - III, B - I, C - II, D - IV$

  4. $A - III, B - I, C - IV, D - II$


Correct Option: C
Explanation:

The metals which are placed high in the reactivity series are obtained by electrolysis, middle metals by reduction using carbon, lower by heating alone and metals at bottom of the series are found in native state.

Which of the following is/are true about silver plating?

  1. The process of depositing a thin layer of silver electrolytically on metal surface is called silver plating.

  2. The article to be silver plated is made the anode

  3. Cathode consists of pure silver.

  4. The bath contains a solution of potassium argentocyanide $(AgNO _3+ \text { excess of KCN})$


Correct Option: A,D
Explanation:

The following are true about silver plating.
The process of depositing a thin layer of silver electrolytically on metal surface is called silver plating.
The article to be silver plated is made the cathode.
Anode consists of pure silver.
The bath contains a solution of potassium argentocyanide $(AgNO _3+ \text { excess of KCN})$

Classify the following as physical or chemical properties.
The composition of a sample of steel is 98% iron, 1.5% carbon and 0.5% other elements.

  1. Physical property

  2. Chemical property

  3. Both $A$ and $B$

  4. Neither $A$ or $B$


Correct Option: A
Explanation:

Steel is an alloy of various metals, physically combined together in a fixed amount by weight, to improve the physical and mechanical properties.

__and ___are alloys of copper.

  1. Brass and bronze

  2. Brass and alloy steel

  3. Copper pyrites and malachite

  4. Copper glance and cuprite


Correct Option: A
Explanation:

  • A homogeneous mixture of two or more elements is known as Alloys.
  • There are various alloys of copper:
Brass-Copper with zinc, Bronze-Copper with tin, and Coinage alloy-copper with nickel.
  • Hence, option  A is correct.

Which of the following is/are true regarding uses of silver?

  1. Silver leaves are used in filling teeth.

  2. Silver amalgam is used in Ayurvedic and Yunani medicines.

  3. Silver is used in silver plating.

  4. It is used in the preparation of silver salts used in silvering of mirrors, photography and medicine.


Correct Option: C,D
Explanation:

The following are true regarding uses of silver.
Silver amalgam is used in filling teeth.
Silver leaves are used in Ayurvedic and Yunani medicines.
Silver is used in silver plating.
It is used in the preparation of silver salts used in silvering of mirrors, photography and medicine.

An element is sonorous and highly ductile. Under which category would you classify this element? What other characteristics do you expect the element to possess?

  1. Metal

  2. Non-Metal

  3. Metalloid

  4. Semi-conductor


Correct Option: A
Explanation:

Metal

Malleable high melting and boiling point, lustrous hard, high density and a good conductor of heat and electricity.

Which of the following is/are true regarding the physical properties of silver?

  1. It is white, lustrous, lightweight metal.

  2. It is very malleable and ductile, coming before gold in this property.

  3. It is poor conductor of heat and electricity.

  4. None of the above.


Correct Option: D
Explanation:

The following  are true regarding the physical properties of silver.
It is white, lustrous, heavy metal.
It is very malleable and ductile, coming next to gold in this property.
It is best conductor of heat and electricity.

The percent of silver in silver - copper alloy used for jewellery purposes has _______ % silver.

  1. 20

  2. 40

  3. 60

  4. 80


Correct Option: D
Explanation:

The percent of silver in silver - copper alloy used for jewellery purposes has 80 % silver and 20% copper. Silver copper alloy is used in coins, ornaments, silver ware, decoration pieces, etc.

Molten silver absorbs _________ which is given off on cooling causing violent spurting. This is called splitting of silver and can be prevented by covering the molten metal with a layer of charcoal.

  1. carbon monooxide

  2. carbon dioxide

  3. carbon

  4. charcoal


Correct Option: B
Explanation:

Molten silver absorbs oxygen which is given off on cooling causing violent spurting. This is called splitting of silver and can be prevented by covering the molten metal with a layer of charcoal.

You have three solids. One is a metal; one is an ionic compound; one is a molecular/covalent compound. You test all three solid samples to identify their bonding.

Sample Appearance Melting Point $(^{\circ}C)$ Conductivity
A Shiny $962$ conductive
B Crystalline $801$ conductive in aqueous solution
C Powdery $186$ not conductive

Based on this data, identify the type bonds present in each sample.

  1. Sample A is a metal.

    Sample B is a salt.

    Sample C is a molecule.

  2. Sample A is a molecule.

    Sample B is a metal.

    Sample C is a salt.

  3. Sample A is a salt.

    Sample B is a metal.

    Sample C is a molecule.

  4. Sample A is a molecule.

    Sample B is a salt.

    Sample C is a metal.


Correct Option: A
Explanation:

Ans : (A) Sample $A$ is metal

(B) Sample $B$ is a salt
(C) Sample $C$ is a molecule
Note : - (1) We know that metal possers shiny properties and it is a good conductor of electricity.
(2) Ionic salt is dissolved in water make an electrically conductive solution. Ionic compound is formed from strong electrostatic interaction between ions which result in a higher melting point.
(3) Molecule do not have free $e^{\ominus}$ to conduct the Electricity.

You may be "shocked" to discover that metals are good conductors of electricity. Which of the following statements best explains why metals behave in this way?

  1. Metallic bonding can be described as an "electron sea" with mobile valence electrons.

  2. Metals tend to have higher densities than nonmetals.

  3. Metals tend to have higher melting points than nonmetals.

  4. Metals tend to have rather large values for electronegativity.


Correct Option: A
Explanation:

Ans : (A) Metallic bonding can be described as an 'Electron Sea' with mobile valence Electron.

Note: - In metals, the outer Electrons of atom belong to a 'cloud' of delocalised $e^{\ominus}$. They are no longer firmly held by a specific atom, but instead they can move freely through the lattice of positive metals ions. $\therefore$ Metals are good conductor of Electricity.

Metals generally extracted by electrolysis of their fused salts are highly:

  1. electropositive 

  2. electronegative

  3. depends on temperature

  4. depends on impurities in the metal


Correct Option: A

A metal which is lighter than water is:

  1. lithium

  2. gold

  3. silver

  4. iron


Correct Option: A
Explanation:
Lithium has a density of (0.534 g/cm3) which is lower than water (1 g/cm$^3$). Two other metallic elements are less dense than water. Potassium has a density of 0.862 g/cm$^3$ while sodium has a density of 0.971 g/cm$^3$. All of the other metals on the periodic table are denser than water. While lithium, potassium, and sodium are all light enough to float on water, they are also highly reactive.

Sodium and potassium  are soft even after being metals because of:

  1. strong intermolecular forces

  2. weak cohesive forces

  3. high melting point

  4. low boiling point


Correct Option: B
Explanation:

Hardness of a metal is determined by the strong cohesive forces between the atoms. The cohesive forces between atoms of these metals are very weak. The bonding in these metals is weak and electrons are not located over a single atom but over a number of atoms. The weak bonding results in softness of metal.

Metals have:

  1. high melting and boiling point

  2. low melting and boiling point

  3. high melting and low boiling point

  4. low melting and high boiling point


Correct Option: A
Explanation:

1) High melting and boiling point

2) Metallic bonding is the strong attraction between closely packed positive metal ions and a 'sea' of delocalised electrons.

3) The attraction between the metal ions and the delocalised electrons must be overcome to melt or to boil a metal.

4) These attractive forces are strong, so metals have high melting and boiling points.

In vapour state a metal is mono atomic.

  1. True

  2. False


Correct Option: A
Explanation:

There are no definitive chemical bonds between two metal atoms in a lattice. They all are held together by the so-called metallic bond. The valence electrons are not shared between metal atoms. Hence they exist as a single metal atom in their lattice unit. 

However we need to apply so much energy to convert it into vapour . And when these change to vapour then no any electron is shared between any metal atom and stay in monoatomic.
When the energy is lowered these again form lattices.

Arrange $Si, Be, Mg, Na$ and $P$ in the increasing order of metallic character:

  1. $P<Be<Si<Mg<Na$

  2. $P<Si<Be<Mg<Na$

  3. $Si<P<Mg<Na<Be$

  4. $Na<Mg<Be<Si<P$


Correct Option: B
Explanation:

metallic character increases down the group and decreases along the period as we move left to right. Hence the order of increasing metallic character is 

P to Na.

The most reactive metal among the following is:

  1. Fe

  2. Pt

  3. Ni

  4. Co


Correct Option: A
Explanation:
The reactivity series is sometimes quoted in the strict reverse order of standard electrode potentials, when it is also known as the "electrochemical series":

$Li > Cs > Rb > K > Ba > Sr > Na > Ca > Mg > Be > Al > H( water) > Mn > Zn > Cr > Fe > Cd > Co$
$ > Ni > Sn > Pb > H(in acids) > Cu > Fe(+3) > Hg > Ag > Pd > Ir > Pt > Au $

So, according to this series, Iron is most reactive than $Pt, Ni, Co$

Platinum metal can be dissolved in:

  1. hot conc. HCl

  2. hot conc. $HNO _3$

  3. hot dil. $H _2SO _4$

  4. a mixture of conc. HCl and $HNO _3$


Correct Option: D
Explanation:
  • Traditional aqua regia is a mixture of concentrated nitric and hydrochloric acids in a ratio of 1:3 that can dissolve noble metals such as gold, platinum and palladium, even though the metals are not soluble in either acid alone.
  • Hence option D is correct answer.

A bar of zinc generates a characteristic sound when bent, similar to_________.

  1. Tin cry

  2. Water splashing

  3. Glass breaking

  4. None of above


Correct Option: A
Explanation:

A bar of zinc generates a characteristic sound when bent, similar to tin cry. A tin cry is the characteristic sound heard when a bar of tin is bent. Variously described as a "screaming" or "crackling" sound, the effect is caused by the crystal twinning in the metal.

Zinc has a melting point of :

  1. $233^\circ C$

  2. $219^\circ C$

  3. $333^\circ C$

  4. $419^\circ C$


Correct Option: D
Explanation:

The metal Zinc has a melting point of $419^\circ C$.

Greyish white metal which is a good conductor of electricity and heat , has a boiling point of $920^\circ C$ is :

  1. aluminium.

  2. tin.

  3. iron.

  4. zinc.


Correct Option: D
Explanation:

Greyish white metal which is a good conductor of electricity and heat and has a boiling point of $920^\circ C$ is zinc.


Hence, the correct option is $D$.


Why are metals solid in state?

  1. The atoms are attached by weak van der waals forces

  2. They gain electrons very easily

  3. They have a high boiling point

  4. They have a high intermolecular forces


Correct Option: D
Explanation:

Most metals are solids because the intermolecular forces between the atoms of metals are quite large. This reduces the interstitial space and so they acquire a definite shape. Room temperature is not enough to provide them required kinetic energy to overcome their forces of attraction or convert its state. Thus, they remain solid at room temperature.

A metal which can be cut with a knife is:

  1. iron

  2. sodium

  3. copper

  4. zinc


Correct Option: B
Explanation:

Sodium and Potassium metals are the two metals which are soft and can be cut with a knife.

Most of the metals:

  1. are hard

  2. have lustre

  3. are good conductors of electricity

  4. all of the above


Correct Option: D
Explanation:
Metals have these typical physical properties:
  • Lustrous (shiny)
  • Hard
  • High density (are heavy for their size)
  • High tensile strength (resist being stretched)
  • High melting and boiling points.
  • Good conductors of heat and electricity. It can be followed that all of the above are correct

Silver jewellary turns black on long exposure to air. This is due to the formation of:

  1. $Ag _2O$

  2. $Ag _3N$

  3. $Ag _2O+Ag _3N$

  4. $Ag _2S$


Correct Option: D
Explanation:

Silver is stable in pure water and air but tarnishes when it is exposed to air or water containing hydrogen sulfide, the latter forming a black layer of silver sulfide which can be cleaned off with dilute $HCl$.

$2Ag+H _2S\rightarrow \underset {black.}{Ag _2S}+H _2$

Metals can be drawn into thin wires, this property is called:

  1. ductility

  2. elasticity

  3. volatility

  4. malleability


Correct Option: A
Explanation:

$Ductility$ is when a solid material stretches under tensile stress. If a material is ductile it can be stretched into a wire. 


When a mechanical force is applied to a material its shape changes for a certain period of time after removing the external force it regains it shape and structure, this property of a material is called $elasticity$. Elasticity of a material is measured by Young's modulus of elasticity.


In chemistry, $volatility$ is a material quality which describes how readily a substance vaporizes. At a given temperature and pressure, a substance with high volatility is more likely to exist as a vapor, while a substance with low volatility is more likely to be a liquid or solid.

$Malleability$, a similar property, is a material's ability to deform under pressure (compressive stress). If malleable, a material may be flattened by hammering or rolling and turn into thin sheets.

Option $(A)$ is correct.

Metals can be beaten into thin sheets. This property is called:

  1. ductility

  2. elasticity

  3. volatility

  4. malleability


Correct Option: D
Explanation:

Malleability is a substance's ability to deform under pressure ( compressive stress). If malleable, a material may be flattened into thin sheets by hammering or rolling. Malleable materials can be flattened into metal leaf. Many metals with high malleability also have high ductility.

A needle and a knife belong to the same group because:

  1. they are transparent

  2. they are hard and magnetic

  3. they float on water

  4. they are poor conductors of heat


Correct Option: B
Explanation:

As we know that a needle and a knife both are made up of metals. 

Metals are not transparent, their density is higher than water so they sink easily in water and metals are a good conductor of heat and electricity.
But metals are hard (except some exception like $Hg,\ Na$ etc) and they are magnetic.

Metals are usually:

  1. good conductors of heat

  2. good conductors of electricity

  3. good elastic substances

  4. all of the above


Correct Option: D
Explanation:
Metals have these typical physical properties:
  • Lustrous (shiny)
  • Hard.
  • High density (are heavy for their size)
  • High tensile strength (resist being stretched)
  • High melting and boiling points.
  • Good conductors of heat and electricity.
  • Elastic materials 

What is the change in color when $ZnO$ is heated?

  1. Yellow

  2. Violet

  3. Green

  4. Blue


Correct Option: A
Explanation:
Zinc Oxide is originally a white powder. When heated up, it turns yellow but does not decompose and when it is removed from the heat it gradually goes back to its original white colour.

Hence, option A is correct.

Which of the following statements are true about metals?

  1. Valence band overlaps with conduction band.

  2. The gap between valence band and conduction band is negligible.

  3. The gap between valence band and conduction band cannot be determined.

  4. Valence band may remain partially filled.


Correct Option: A
Explanation:

Valence band overlaps with conduction band for the conductivity of metal.

Which one of the following oxidation states is not possible in metal carbonyls ?

  1. +1

  2. 0

  3. -1

  4. +2


Correct Option: B

Most balloons, tyres and footballs are made-of rubber. This is because rubber is:

  1. naturally available

  2. cheap

  3. an electrical insulator

  4. soft and flexible


Correct Option: D
Explanation:

Prior to rubber tires, metal and wood were the materials in use. However it was found that natural Rubber provides better cushioning, makes less noise. Further rubber deforms under weight /force which results in larger contact patch with the road than with metal/wood tires of same diameter/width. During cornering at high speeds, the deformation of sidewall and larger contact area improves the traction or grip on the road increasing safety.

Eventhough a cinema hall is a place prone to fire hazards, the interiors are mostly made of wood or wood based panels. Why is this so ?

  1. Wood does not catch fire easily

  2. Wood is opaque

  3. Wood can absorb sound

  4. Wood is very commonly available


Correct Option: C
Explanation:

Wood is a good sound absorber. if it will be of some different material then there will be echo(a reflection of sound) in the hall and the sound will not be clear.

The metallic character of elements ............. in a group from top to bottom.

  1. Increases

  2. Decreases

  3. remains constant

  4. shows indefinite behaviour


Correct Option: A

Sulphur extracted from natural sources is called roll sulfur.

  1. True

  2. False


Correct Option: B
Explanation:

Sulphur extracted from natural sources is called brimstone. 

B is correct

Which of the following element is not in the liquid state at room temperature?

  1. $Hg$

  2. $Li$

  3. $Ga$

  4. $Br$


Correct Option: B
Explanation:
Bromine and mercury are metal which is liquid at room temperature. Gallium a brittle solid at low temperatures, and a liquid at temperatures greater than $29.76^o C$ (slightly above room temperature).Thus gallium is liquid at room temperature.
Bromine is a liquid because electrons are well apart from the nuclei so they are easily distorted .Intermediate intermolecular forces exists and thus it is in liquid state.
 Lithium  is a solid at room temperature.
Non-metals are usually poor conductors of heat and electricity. They are non-lustrous, non-sonorous, non-malleable and are coloured. The non-metal which is known to form the largest number of compounds is:
  1. carbon

  2. sulphur

  3. nitrogen

  4. chlorine


Correct Option: A
Explanation:
Carbon is a non-metal and is  known to form the largest number of compounds due to two reasons:

  1. Catenation - The ability of carbon to form bonds with the atoms of itself resulting in the large chains and rings of carbon. It causes large no. of chain and ring compounds.
  2. Tetravalency - Due to tetravalency, carbon can form bonds with other tetravalent elements and monovalent elements like hydrogen, chlorine, bromine etc.

Hence, option A is correct.

Which among the following non-metal is liquid at room temperature?

  1. Chlorine

  2. Bromine

  3. Mercury

  4. Phosphorous


Correct Option: B
Explanation:

Mercury and bromine both are present in liquid state at room temperature but mercury is metal and bromine is non-metal.

So, liquid non-metal at room temperature is bromine.

One metal which is not ductile at room temperature is:

  1. $Cu$

  2. $Sn$

  3. $Pb$

  4. $Hg$


Correct Option: D
Explanation:

$Hg$ is liquid at room temperature and cannot be beaten into thin wire; thus is not ductile at room temperature. All other metals $Cu, Sn ,  Pb$ are ductile at room temperature. 

Which of the following elements cannot be beaten into thin wires?

  1. $O$

  2. $P$

  3. $S$

  4. All of these


Correct Option: D
Explanation:

Non-metals are generally non-ductile and cannot be beaten into thin wires. All given elements $O,P,S$ are non metals and do not have property of ductility. 

Non-metals are brittle while metals are ductile. Why?

  1. Because of lesser extent of bonding in non-metals

  2. Because of greater extent of bonding in non-metals

  3. Because of smaller size of non-metallic atoms

  4. Because of lower conductivity of non-metals


Correct Option: A
Explanation:

The basic difference between metals and non-metals is the extent of bonding.Metals have very high extent of bonding than that in non-metals which makes the metal malleable. and non-metals brittle.

Which allotrope of carbon do not conduct electricity?

  1. Graphite

  2. Diamond

  3. Fullerene

  4. Both b and c


Correct Option: D
Explanation:

Carbon is a non-metal which have allotropic form that is graphite, diamond and fullerene. Out of this three only graphite is conductor of electricity. Diamond and fullerene do not conduct electricity.

Which characteristics are required for a element to behave as electrical conductor?

  1. It should have valence electron

  2. It should have free electron

  3. It easily provide electron to other element

  4. Both $B$ and $C$


Correct Option: D
Explanation:

Electrical conductors elements have free electrons, which they can easily provide to conduct electricity. This characteristics are generally available in metals.

Which of the following is the largest in size?

  1. $Br$

  2. $I$

  3. $I^-$

  4. $I^+$


Correct Option: C
Explanation:

Answer : $I^{\ominus}$

(1) We know that from top to bottom atomic size is increases. So $I$ its having higher atomic size then $Br$.
(2) In $I, I^{\ominus}$ and $I^{\oplus}$
$I^{\ominus}$ have the largest atomic size because $I^{\ominus}$ has one extra electron in its valence shell which lead to increase in atomic size.
$\therefore I^{\ominus} > I > I^{\oplus} > Br$.

 Which of the following non-metal is lustrous?

  1. Diamond

  2. Iodine

  3. Both $A$ and $B$

  4. None of the above


Correct Option: C
Explanation:

Diamond and iodine both are non metal and lustrous.

Which one is the softest solid non-metal among the following?
Diamond, Oxygen, Sulphur, Bromine

  1. Diamond

  2. Oxygen

  3. Sulphur

  4. Bromine


Correct Option: C
Explanation:

Most of the solid non-metals are quite soft. For example - sulphur and phosphorous are solid non-metals which are quite soft.

Which of the following when stretched, break into pieces?

  1. Calcium

  2. Phosphorus

  3. Iron

  4. Radium


Correct Option: B
Explanation:

When sulphur or phosphorus is stretched, they break into pieces. Non metals are non-malleable non-ductile.

Which of the following is/ are property of non-metals?
(a) Non-metals are malleable.
(b) Non-metals are non ductile.
(c) Non-metals are brittle.

  1. a, b

  2. b, c

  3. a, c

  4. a, b, c


Correct Option: B
Explanation:

Non-metals are non-malleable, non-ductile when they are beaten with hammer or stretched they break into pieces, so they are brittle.

Non-metals are present in which state?

  1. Solid

  2. Liquid

  3. Gaseous

  4. All of the above


Correct Option: D
Explanation:

Answer: all of the above 

Most of metal exist in two out of three states of matter at room temperature
Eg: gases- oxygen,  solid-carbon

Only bromine exist in liquid state at room temperature.

Graphite is the only non-metal which is good conductor of electricity.

  1. True

  2. False


Correct Option: A
Explanation:
Graphite is composed of carbon atoms which are situated in layers. Because of that electron are free to move and conduct the electricity. Although it is a non-metal, good conductor of electricity. 

Chlorine is greenish yellow gas.

  1. True

  2. False


Correct Option: A
Explanation:

It is a pale green gas and is used in cleaning products. Chlorine is an greenish-yellow gaseous element. Its atomic number is 17, and is one of the class called halogens in the periodic table. Large concentration of chlorine are dangerous.

A non-metal which is a good conductor of electricity is:

  1. graphite

  2. hydrogen

  3. sodium

  4. mercury


Correct Option: A
Explanation:

1) Graphite is soft and slippery because there are only weak intermolecular forces between its layers. Graphite is a good conductor of heat and electricity.

2) Graphite can conduct electricity because of the delocalised (free) electrons in its structure.

3) These arise because each carbon atom is only bonded to 3 other carbon atomsHowever, in diamond, all 4 outer electrons on each carbon atom are used in covalent bonding, so there are no delocalised electrons.

4) These electrons in graphite are free to move through the structure.

Iodine is a non-metal which has metallic lusture.

  1. True

  2. False


Correct Option: A
Explanation:

Its because going down the group the size of the atom increases because of shielding effect due to which the interaction between the atom and the outermost electron decreases so these electrons on the surface of iodine become excited by absorbing heat energy from light so when they release this energy and come to their normal state, they emit this light so it appears that they have lustrous surface.

Which of the following does not conduct electricity in its molten state?

  1. Iron

  2. Magnesium oxide

  3. Lithium fluoride

  4. Sulphur


Correct Option: D
Explanation:

Sulphur is a non-metal so it does not conduct electricity. Iron is a metal so it conducts electricity Magnesium oxide and Lithium fluoride are ionic compounds that contains ions which conducts electricity in molten state.

Bromine is the only liquid non-metal.

  1. True

  2. False


Correct Option: A
Explanation:
Bromide is only liquid non metal ,mercury is liquid metal crallium is liquid metal.

Generally, non-metals are not good conductors of electricity. 

Which of the following is a good conductor of electricity?

  1. Diamond

  2. Graphite

  3. Buckminster fullerene

  4. Sulphur


Correct Option: B
Explanation:

Graphite has a layered planar structure. Carbon atoms in the plane are bonded covalently with only three of the four potential bonding sites. The fourth electron is free to migrate in the plane making graphite electrically conductive.

At room temperature liquid non-metal is 

  1. Carbon

  2. Bromine

  3. Mercury

  4. Iodine


Correct Option: B
Explanation:

At room temperature liquid non-metal is bromine.

The non-metal having shining surface is:

  1. sulphur

  2. phosphorus

  3. iodine

  4. carbon


Correct Option: C
Explanation:

It's because going down the group the size of the atom increases because of the shielding effect due to which the interaction between the atom and the outermost electron decreases.

 So these electrons on the surface of iodine become excited by absorbing heat energy from light. so when they release this energy and come to their normal state, they emit this light so it appears that they have a shining surface.

So, the correct option is $C$

Which of the following are properties of non-metals?

  1. Low melting point

  2. Poor conductor of electricity

  3. Low densities

  4. All of these


Correct Option: D
Explanation:
Common Properties of non-metals-
  • High ionization energies.
  • High electronegativities.
  • Poor thermal conductors.
  • Poor electrical conductors.
  • Brittle solids - not malleable  or ductile.
  • Little or no metallic lustre.
  • Gain electrons easily.
  • Dull, not metallic-shiny, although they may be colorful.
  • Low melting point and densities.
  • Lower melting points and boiling point than the metals.

Which of the following is a property of nonmetals?

  1. Low densities

  2. Low melting points

  3. Poor conductor of electricity

  4. All the three


Correct Option: D
Explanation:
Non metals are poor conductor of electricity, low densities, low melting points, non lustrous, brittle in nature, non ductile and not malleable in nature.
So, answer is D.

By dropping a drop of water on a glowing electric bulb, it bursts. This is because glass is a _________.

  1. good conductor of heat

  2. bad conductor of heat

  3. transparent substance

  4. good conductor of electricity


Correct Option: B
Explanation:

1) The glass is actually an insulator. 

2) It doesn't allow the flow of electrons easily from atom to atom, as seen in substances like copper, and other metals which are excellent conductors of both heat and electricity. 

3) Insulators have electrons that are held tightly which means they aren't shared between other atoms.

Which of the following is a good conductor of electricity?

  1. Diamond

  2. Graphite

  3. Both A and B

  4. None of the above


Correct Option: B
Explanation:

Diamond and graphite are allotropes of carbon. Graphite has carbon molecules held together by weak van der Waal's forces of attraction and they have loosely bound electrons which are responsible for conducting electricity, while diamond is the hardest and strongest material in which all the molecules are bound by strong bonding between carbon tetrahedrons held by strong forces of attraction and so, they do not have free or loosely bound electrons to conduct electricity.

Diamond and graphite are good conductors of electricity.

  1. True

  2. False


Correct Option: B
Explanation:

Graphite is able to conduct electricity, due to delocalization of the pi bond electrons above and below the planes of the carbon atoms. These electrons are free to move, so are able to conduct electricity.
In diamond, all four outer electrons of each carbon atom are 'localized' between the atoms in covalent bonding. The movement of electrons is restricted and diamond does not conduct an electric current.

Thus, graphite is a good conductor and diamond is not. 
Option "B" is correct.

Compare the physical properties of metals and non-metals in general with reference to melting point.

  1. Both have low melting point

  2. Both have high melting point

  3. Metals have low melting point while non-metals have high melting point

  4. Metals have high melting point and non-metals have low melting point


Correct Option: D
Explanation:

Metals have high melting and boiling point. Tungsten has the highest melting point where as silver has low boiling point. Sodium and potassium have low melting points. Non metals have low melting point.

State whether true or false :

Diamond and iodine are non-metals which are lustrous.

  1. True

  2. False


Correct Option: A
Explanation:

In case of iodine, the large size of the atom results in low shielding of valence electrons. 


Upon absorption of light or heat by these electrons, the de-excitation of the absorbed heat from the surrounding emit light so it appears that they have lustrous surface.


The sparkling shine of the diamond comes from its cut, clarity, refractive index and reflection. 

The natural diamonds found from the earth is dull and dim. Total internal reflection partially provides the brilliance and shine to the diamond. 

When light strikes the diamond, it gets refracted and get separated into individuals colors. Diamonds normally have high refractive index thus providing a brilliant shine to the diamond.

Therefore Diamond , graphite & iodine are nonmetals which are lustrous because of their crystal structure.

Therefore, option A is correct.

Plastic sulfur has no sharp melting point.

  1. True

  2. False


Correct Option: B
Explanation:

Amorphous or plastic sulfur is produced by rapid cooling of molten sulfur e.g. by pouring it in cold water. It has helical form and metastable at room temperature reverting to its crystal allotrope and have sharp melting point.

Which of the following are uses of sulphur?

  1. Sulphur is used in preparation of conducting wires

  2. A mixture of zinc and sulphur on heating with sulphur produces a greyish residue of zinc sulphide

  3. Sulphur is an element belonging to VI A group

  4. Sulphur is a nonmetallic element.


Correct Option: B,C,D
Explanation:

Zinc on heating with sulphur produces a greyish residue of zinc sulphide.
Sulphur is an element belonging to VI A group.
Sulphur is a nonmetallic element.

Non-metals have properties similar to that of metals.

  1. True

  2. False


Correct Option: B
Explanation:

Non-metals have properties similar to that of metals , This  Statement is false because:

Properties of metals : 

Metals are solid at room temp. 
They are generally hard and strong. 
They have metallic lustre. 
They have high melting and boiling points. 
They are good conductors of heat and eletricity. 
Metals are sonorous. 
Most metals have high tensile strength. 
They are malleable. 
They are ductile. 
They have high densities. 


Properties for non-metals: 

Non-metals are glasses or solids at room temp. except bromine. 
They are not as hard as metals and have low tensile strengths. 
They do not have lusture. 
They are bad conductors of heat and electricity. 
Non-metals are brittle, they are neither malleable nor ductile. 
They usually have low densities. 
They have low melting and boiling points. 
They are non-sonorous. 

Boojho has learnt that non-metals on beating with a hammer are generally broken into pieces. Which of the following is a non-metal?

  1. Iron nail

  2. Aluminium wire

  3. Copper plate

  4. Piece of coal


Correct Option: D
Explanation:

All are metals in the given options iron, aluminium and copper but only carbon is a nonmetal present which is breakable with a hammer.

Generally, non-metals are not lustrous. Which of the following non-metal is lustrous?

  1. Sulphur

  2. Oxygen

  3. Nitrogen

  4. Iodine


Correct Option: D
Explanation:

Lustre means shine. Shining metals are also called lustrous metal. For example, gold. Non-metals such as sulphur, oxygen, nitrogen are non-lustrous but iodine is a greyish black solid and crystals have a metallic lustre.

Non-metals do not show ductility due to absence of:

  1. metallic bonds which allow one electron to slip over another

  2. covalent bonds which gives strength

  3. ionic bonds which gives makes it hard

  4. co-ordinate bonds which which gives extra stability


Correct Option: A
Explanation:
Non-metals do not show ductility due to absence of metallic bonds which allow one electron to slip over another. High degrees of ductility in metals occur due to metallic bonds. In metallic bonds valence shell electrons are delocalized and shared between many atoms. The delocalized electrons allow metal atoms to slide over one another without being subjected to strong repulsive forces that would cause non-metals to shatter.

The elements which partially conduct electricity are called as __________.

  1. Conductors

  2. Insulators

  3. Semiconductors

  4. None of these


Correct Option: C
Explanation:

Semiconductors are the elements which conduct electricity but in less quantity. Hence, they are called as semiconductors.

______________ is the non-metal which conduct electricity.

  1. Carbon

  2. Nitrogen

  3. Oxygen

  4. Sulphur


Correct Option: A
Explanation:

Carbon is the non-metal which conduct electricity in the form of graphite which is it's allotrope. Allotropes are the compound of the element in which they have same chemical properties but different physical properties. 

Which is the lightest gas?

  1. ${N} _{2}$

  2. $He$

  3. ${O} _{2}$

  4. ${H} _{2}$


Correct Option: D
Explanation:

Hydrogen and helium are the two lightest gasses,  they weigh so less that helium balloons and hydrogen dirigibles are able to float in the atmosphere.

Non-metals are poor conductors of heat, which are tend to:

  1. be brittle

  2. conduct an electrical current

  3. have a shiny luster

  4. be malleable

  5. lose electrons


Correct Option: A
Explanation:
Non metals tend to gain or share electrons when they react with other substances. 
They are poor conductors of heat and electricity. 
They are non-lustrous and have various colors. 
They are brittle and non-malleable hard or soft. 

Non metals are never used in cooking utensils because:

  1. they are good conductor of heat

  2. they are bad conductor of heat

  3. they can't cook food properly

  4. they are not attractive


Correct Option: B
Explanation:

Non-metals are poor conductor of heat. So, they can't be used for cooking utensils.  

Non-metals do not have lustre which means:

  1. they do not have a shining surface

  2. they can't produce sound

  3. they can't conduct heat

  4. none of the above


Correct Option: A
Explanation:

Non metals do not have  lustre which means that non-metals do not have a shining surface. That means they have a dull appearance.

Brittleness is a characteristic property of:

  1. gaseous non-metals

  2. liquid non-metals

  3. solid non-metals

  4. none of the above


Correct Option: C
Explanation:

Brittleness is a characteristic property of non-metals. And here, we consider solid non-metals only. It is not applicable to liquid or gaseous non-metals.

Which of the following is not a property of non-metals?

  1. Non-metals can be stretched into thin wires

  2. Non-metals are not ductile

  3. Non-metals are not malleable

  4. Non-metals break easily


Correct Option: A
Explanation:

Non-metals are non-malleable and non-ductile. They are brittle. They break easily. So, they are regarded as brittle. They can't be stretched into mines or hammered into sheets.

Iodine cannot be deformed into a wire because:

  1. it is a non-metal

  2. it is brittle

  3. both A and B

  4. none of above


Correct Option: B
Explanation:

Iodine is a non-metal which is brittle in nature, it breaks and shatters easily when hammered. Hence, it cannot be used to make thin wires and is non-ductile.

Which of the following is non-ductile?

  1. Selenium

  2. Copper

  3. Aluminium

  4. Magnesium


Correct Option: A
Explanation:

Selenium is a chemical element with symbol Se and atomic number 34. It is a nonmetal with properties that are intermediate between those of its periodic table column-adjacent chalcogen elements sulfur and tellurium. As it a non-metal, it cannot be deformed into a wire as it is brittle.

Why are non-metals not ductile?

  1. They are hard

  2. They are soft

  3. They are brittle

  4. All of above


Correct Option: C
Explanation:

Non-metals are not ductile because they are brittle elements. They break easily. Such non-metals cannot be deformed by a hammer or rolling. 

Which type of elements show brittleness?

  1. Metals

  2. Non-metals

  3. Metalloid

  4. None of the above


Correct Option: B
Explanation:

Non-metal are neither malleable nor ductile. Non metals are brittle.

Non-metals are:

  1. soft

  2. hard

  3. brittle

  4. all of above


Correct Option: C
Explanation:

Non-metals are very brittle and cannot be rolled into wires or pounded into sheets. They break easily when hit by a hammer.

Which of the following non-metal is hard yet brittle?

  1. Graphite

  2. Selenium

  3. Sulphur

  4. Diamond


Correct Option: D
Explanation:

Diamond is the hardest substance known to man with a hardness of 10.0. It is brittle sometimes because it grows in diamond shape crystals, sometimes there are tiny cracks or flaws in the diamond and a hard strike against the crack of course will cause the diamond to crack into many pieces. Crystalline materials have planes of variable shear and normal strengths hence, they fail on fracture mechanism. Also, crystalline nature makes them extremely strong at surface resisting scratch.

Why non-metals have a dull appearance?

  1. They have many free electrons

  2. They gain electrons easily

  3. They do not have lustre

  4. All of above


Correct Option: C
Explanation:

Non-metals vary greatly in appearance. They do not have lustre. As it does not have any free electrons light falling on non-metals does not reflect and hence non-metals are not shiny. Hence, they have a very dull appearance.

Which of the following example is a poor conductor of electricity?

  1. Oxygen

  2. Aluminium

  3. Gold

  4. Silver


Correct Option: A
Explanation:

Oxygen is a non-metal. Non-metals do not have enough free electrons to pass electricity. Electrons in non-metals are held tightly, they are not allowed to move freely .

Why are non-metals poor conductors of electricity?

  1. They have high melting point

  2. They vibrate at high speed

  3. They do not have free electrons

  4. All of above


Correct Option: C
Explanation:

Non-metals are not dense enough and do not have enough free electrons to pass electricity efficiently. Electrons in non-metals are held tightly , they are no allowed to move freely .

All non-metals are bad conductor of heat and electricity.

  1. True

  2. False


Correct Option: B
Explanation:

Most of the non-metals are bad conductor of heat and electricity. But there are some non-metals which conduct electricity for example graphite. Due to presence of free electron in it.

The non-metal which is liquid at room temperature is:

  1. chlorine

  2. fluorine

  3. bromine

  4. iodine


Correct Option: C
Explanation:

Bromine is the only non-metal which is liquid and diatomic molecule at room temperature. 

It is a dense, reddish-brown liquid evaporating at standard temperature and pressure to give an orange vapour. It is one of the only two elements on the periodic table that are liquids at room temperature other than mercury.

Hence, option $C$ is correct.

Which among the following is a non-metal?

  1. Bromine

  2. Zinc

  3. Sodium

  4. Iron


Correct Option: A
Explanation:

Bromine is a liquid non-metal. Rest others are metals.

Which of the following is not a correct statement?

  1. Non-metals melt at low temperature

  2. Non-metals are generally bad conductors of heat and electricity

  3. Non-metals are non-sonorous

  4. Non-metals are malleable


Correct Option: D
Explanation:

Non-metals are malleable, is an incorrect statement.

A mirror is:

  1. opaque

  2. transparent

  3. translucent

  4. none of these


Correct Option: A
Explanation:

A silver glass mirror is an ordinary mirror, coated on its back surface with silver, which produces images by reflection. This kind of glass mirror is produced by coating a silver, copper film and two or more layers of waterproof paint on the back surface of float glass, which perfectly resists acid and moisture.

As it reflect all the light falling on it and we can see through it so it is a opaque.

Which of the following is suitable to make raincoats?

  1. Cotton

  2. Plastic

  3. Silk

  4. Wool


Correct Option: B
Explanation:

Plastic is waterproof, it cannot absorb water while the others can.

Which non-metal has semi-conductor property?

  1. Boron

  2. Carbon

  3. Silicon

  4. Magnesium


Correct Option: C
Explanation:

Silicon is a tetravalent metalloid. Pure silicon is used to produce silicon wafers in the semiconductor industry. Pure silicon is an intrinsic semiconductor as it conducts electron holes and increases electrical conductivity. Silicon is doped with other microelements to increas its conductivity. It is used in transistors, solar cells, semiconductor devices.

Which of the following is a lustrous non-metal?

  1. Chlorine

  2. Nitrogen

  3. Iodine

  4. Florine


Correct Option: C
Explanation:

Non-metals do not have luster. They do not reflect light from their surface (exception diamond and iodine). Non-metals have dull appearance.

Lustrous non-metal is :

  1. Diamond

  2. Iodine

  3. Sulphur

  4. Both A and B


Correct Option: D
Explanation:

Non-metals do not have lustre. They do not reflect light from their surface. Non-metals have dull appearance. Diamond and iodine are two exceptions and are lustrous non-metal.

Which non-metal has a shining surface?

  1. Graphite

  2. Phosphorous

  3. Sulphur

  4. None of the above


Correct Option: A
Explanation:

Graphite is the most stable form of carbon and so it is used as the standard state for defining the heat and formation of carbon compounds. It has a layered planar structure and the bonding between the layers is vander waals bonds. It is a non metal with shining surface.

The non-metallic mineral among the following is :

  1. graphite

  2. chromite

  3. bauxite

  4. tungsten


Correct Option: A
Explanation:

Chromite is an ore of chromium, bauxite is an ore of aluminium and tungston are metallic in nature while graphite is an allotrope of carbon and a carbonaceous compound. It is a very soft allotrope of carbon while other allotrope of carbon diamond is the hardest known element on this earth. This is because of the chemical structure of graphite which shows slippery nature of layers of carbon and presence of loose electrons.

Non-metal that has a metallic lustre and sublimes on heating is : 

  1. chlorine

  2. bromine

  3. oxygen

  4. iodine


Correct Option: D
Explanation:

Iodine is an intensely colored solid with an almost metallic luster. This solid is relatively volatile and it sublimes when heated to form a violet-colored gas.

Compare metals and non-metals with particular emphasis on solubility:

  1. Both dissolve in solvent

  2. None of them dissolve in solvent

  3. Metal dissolve while non-metal do not dissolve in solvent

  4. Non-metal dissolve while metal do not dissolve in solvent


Correct Option: D
Explanation:
MetalsThey do not dissolve in solvents except by chemical action. Non-metalsThey dissolve in solvents and can be re-obtained by evaporation. Example: sulphur in carbon disulphide.

All non-metals are solids or gases, except bromine which is liquid non-metal at room temperature.

  1. True

  2. False


Correct Option: A

Which of the following are properties of non-metals?

  1. Lustre

  2. Can form alloys

  3. Amorphous

  4. Non-conductive towards electricity


Correct Option: C,D
Explanation:

The properties of non-metals are:

  1. They are amorphous in nature.
  2. They are not malleable and ductile.
  3. They are poor conductors of heat and electricity.
  4. They do not form alloys.

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