Physical Properties of Metals and Non-metals Questions in English

(N/A) $(i)$ Metal that exists in a liquid state at room temperature $\to$ Mercury $(Hg)$.
$(ii)$ Metal that can be easily cut with a knife $\to$ Sodium $(Na)$ or Potassium $(K)$.
$(iii)$ Metal that is the best conductor of heat $\to$ Silver $(Ag)$.
$(iv)$ Metals that are poor conductors of heat $\to$ Mercury $(Hg)$ and Lead $(Pb)$.

(N/A) Malleable: Substances that can be beaten into thin sheets are called malleable. For example,most metals are malleable.
Ductile: Substances that can be drawn into thin wires are called ductile. For example,most metals are ductile.

(N/A) With the hammer,we can beat the sample. If it can be beaten into thin sheets (i.e.,it is malleable),then it is a metal; otherwise,it is a non-metal.
Similarly,we can use the battery,bulb,wires,and a switch to set up an electrical circuit with the sample. If the sample conducts electricity,the bulb will glow,indicating it is a metal; otherwise,it is a non-metal.
$(b)$ These tests are useful in distinguishing between metals and non-metals because they are based on fundamental physical properties such as malleability and electrical conductivity. These tests are simple,quick,and do not involve any complex chemical reactions.

(N/A) Platinum,gold,and silver are used to make jewellery due to the following reasons:
$1$. Lustre: These metals possess a high degree of metallic lustre,which makes them attractive and suitable for ornaments.
$2$. Low Reactivity: They are noble metals and are very less reactive. They do not react with air,water,or acids under normal conditions,which prevents them from corroding or tarnishing easily.
$3$. Malleability and Ductility: These metals are highly malleable and ductile,allowing them to be easily shaped into intricate designs.

(A) Metals are elements that typically exhibit properties such as luster (shininess),high electrical and thermal conductivity,ductility (ability to be drawn into wires),and malleability (ability to be beaten into sheets).
They are also sonorous,meaning they produce a ringing sound when struck.
Dullness is a characteristic property of non-metals,not metals.
Therefore,metals generally do not show dullness.

(B) The property of metals by which they can be drawn into thin wires is called $ductility$.
$Malleability$ is the property of being beaten into thin sheets.
$Sonorousity$ refers to the property of producing a ringing sound when struck.
$Conductivity$ refers to the ability to conduct heat or electricity.
Therefore, the correct option is $B$.

(C) Aluminium is widely used for making cooking utensils due to the following reasons:
$1$. Good thermal conductivity: It allows heat to pass through the utensil quickly and evenly,which is essential for cooking food.
$2$. High melting point: It ensures that the utensil does not melt or deform when exposed to the high temperatures required for cooking.
Therefore,properties $(i)$ and $(iv)$ are responsible for its use in cooking utensils.

(A) Most metals exist as solids at room temperature due to their strong metallic bonding.
However,Mercury $(Hg)$ is a unique metal that exists in a liquid state at room temperature $(25^{\circ}C)$.
This is due to the weak metallic bonding between mercury atoms,which allows them to move past each other easily at room temperature.

(C) Most non-metals are dull in appearance and do not possess metallic luster.
However,$Iodine$ is an exception among non-metals.
Although it is a non-metal,it exhibits a characteristic shiny or lustrous appearance in its solid state.
Therefore,the correct option is $C$.

(B) $1$. Analyze the electronic configuration of each element:
- $X$ has $2, 8$ electrons. Its valence shell is full (octet complete), so $X$ is a noble gas (Neon).
- $Y$ has $2, 8, 7$ electrons. It has $7$ valence electrons, meaning it needs $1$ electron to complete its octet. Elements that gain electrons are non-metals (Chlorine).
- $Z$ has $2, 8, 2$ electrons. It has $2$ valence electrons, which it can easily lose to achieve a stable configuration. Elements that lose electrons are metals (Magnesium).
$2$. Evaluate the options:
- Option $A$: $X$ is a noble gas, not a metal.
- Option $B$: $Y$ is a non-metal and $Z$ is a metal. This is correct.
- Option $C$: $Z$ is a metal, not a non-metal.
- Option $D$: $Y$ is a non-metal, not a metal.
Therefore, the correct statement is that $Y$ is a non-metal and $Z$ is a metal.

(D) Non-metals are typically poor conductors of electricity because they lack free electrons.
However,$Graphite$,an allotrope of carbon,is an exception.
In $Graphite$,each carbon atom is bonded to three other carbon atoms in the same plane,leaving one valence electron free per carbon atom.
These free electrons allow $Graphite$ to conduct electricity effectively.
Therefore,$Graphite$ is a good conductor of electricity.

(B) Most non-metals exist as solids or gases at room temperature.
Bromine is the only non-metal that exists in a liquid state at room temperature.
Carbon,phosphorus,and sulphur are all solid non-metals under standard conditions.

(A, B, D) Metals are elements that typically have $1, 2,$ or $3$ electrons in their outermost shell.
$(a)$ Electronic configuration $2, 8, 2$: The valence shell has $2$ electrons. This is Magnesium $(Mg)$.
$(b)$ Electronic configuration $2, 8, 1$: The valence shell has $1$ electron. This is Sodium $(Na)$.
$(c)$ Electronic configuration $2, 8, 7$: The valence shell has $7$ electrons. This is a non-metal (Chlorine,$Cl$).
$(d)$ Electronic configuration $2, 1$: The valence shell has $1$ electron. This is Lithium $(Li)$.
Therefore,the metals are $(a)$,$(b)$,and $(d)$.

(N/A) Copper and aluminium are metals that possess very low electrical resistivity,which means they offer minimal resistance to the flow of electric current.
Because of this property,they act as excellent conductors of electricity.
Consequently,they are widely used in electrical wiring and transmission lines to ensure efficient power delivery with minimal energy loss as heat.

(N/A) Good conductors of heat: Silver $(Ag)$ and Copper $(Cu)$.
$(b)$ Poor conductors of heat: Lead $(Pb)$ and Mercury $(Hg)$.

(N/A) The metal that exists in a liquid state at room temperature is Mercury $(Hg)$.
The non-metal that exists in a liquid state at room temperature is Bromine $(Br)$.
Two metals that have a melting point less than $310\ K$ $(37\ ^\circ C)$ are Cesium $(Cs)$ and Gallium $(Ga)$.

(N/A) The metal that exists in a liquid state at room temperature is $Mercury$ $(Hg)$.
The non-metal that exists in a liquid state at room temperature is $Bromine$ $(Br_2)$.

(N/A) The two metals that have very low melting points are:
$(i)$ Caesium $(Cs)$
$(ii)$ Gallium $(Ga)$
These metals are so sensitive to heat that they can melt in the palm of a human hand.

(N/A) Iodine is a non-metal that exhibits luster (lustrous).
Sodium or Potassium are examples of metals that appear dull (non-lustrous) when exposed to air due to the formation of an oxide layer,or more commonly,metals like Iron in its powdered or oxidized form are considered non-lustrous.

(N/A) Metals are sonorous,meaning they produce a ringing sound when struck. Therefore,they are used to make school bells.
$(b)$ Copper is an excellent conductor of electricity with low electrical resistance. Therefore,it is used for making electrical wires.

(N/A) Sodium $(Na)$ is a highly reactive metal that reacts vigorously with oxygen and moisture in the air,so it is stored in kerosene to prevent reaction.
$(b)$ Iodine $(I_2)$ is a non-metal that possesses a characteristic lustrous appearance and is purple-black in colour.
$(c)$ Gallium $(Ga)$ and Caesium $(Cs)$ have very low melting points and melt when held in the palm of a human hand.
$(d)$ Lead $(Pb)$ and Mercury $(Hg)$ are metals that are poor conductors of heat compared to other metals like copper or silver.

(N/A) $(i)$ Sodium is so soft that it can be cut with a knife.
$(ii)$ It has a low density compared to most metals.
$(iii)$ It has a low melting point.

(N/A) $(i)$ Lead is a metal that is not lustrous.
$(ii)$ Mercury is a metal that exists as a liquid at room temperature.
$(iii)$ Gallium and Caesium are metals that have very low melting points.
$(iv)$ Iodine is a non-metal that is lustrous.
$(v)$ Graphite (an allotrope of carbon) is a non-metal that is a good conductor of electricity.

(N/A) Sulphur $(S)$ is a non-metal because:
$1.$ It is brittle in its solid state and possesses low melting and boiling points.
$2.$ It is an electronegative element that forms anions $(S^{2-})$ and acts as a poor conductor of heat and electricity.
$3.$ It reacts with oxygen to form acidic oxides,which dissolve in water to produce acids.
Chemical equation:
$(a) S(s) + O_2(g) \rightarrow SO_2(g)$
$(b) SO_2(g) + H_2O(l) \rightarrow H_2SO_3(aq)$
These properties are characteristic of non-metals,confirming that sulphur is a non-metal.

(N/A) The atomic number of an element is equal to the total number of electrons present in its neutral atom.
For element $X$,the electronic configuration is $2, 8, 2$. The total number of electrons is $2 + 8 + 2 = 12$. Therefore,the atomic number of $X$ is $12$.
For element $Y$,the electronic configuration is $2, 8, 6$. The total number of electrons is $2 + 8 + 6 = 16$. Therefore,the atomic number of $Y$ is $16$.

(N/A) Elements that exhibit properties intermediate between those of metals and non-metals are known as metalloids.
Examples: $Silicon$ $(Si)$ and $Boron$ $(B)$.

(N/A) Sodium $(Na)$ or Potassium $(K)$ are soft metals that can be easily cut with a knife.
$(b)$ Mercury $(Hg)$ is the only metal that exists in a liquid state at room temperature.
$(c)$ Aluminum $(Al)$ has an atomic number of $13$. Its electronic configuration is $(2, 8, 3)$,meaning it has $3$ valence electrons. Boron $(B)$ also has $3$ valence electrons with configuration $(2, 3)$.

(A) Silver $(Ag)$ is considered the best conductor of heat among all metals. Copper $(Cu)$ is also an excellent conductor of heat and is widely used in cooking utensils and electrical wiring.

(A) Metals are good conductors of electricity because they possess a large number of free electrons that can move freely throughout the material.
In contrast,non-metals are insulators because they have very few or no free electrons,which prevents the flow of electric current.

(A) Silicon $(Si)$ is a chemical element with atomic number $14$.
It belongs to group $14$ of the periodic table.
Its electrical conductivity lies between that of a conductor and an insulator.
Materials with such properties are classified as semiconductors.
Therefore,silicon is a semiconductor.

(C) semiconductor is a material that has electrical conductivity between that of a conductor (like copper) and an insulator (like glass).
Germanium $(Ge)$ and Silicon $(Si)$ are the most common examples of semiconductor elements used in electronic devices.
Zinc $(Zn)$,Copper $(Cu)$,and Silver $(Ag)$ are all metals and act as good conductors of electricity.
Therefore,the correct option is $C$.

(C) The earth's crust is composed of various elements. Among all metals, $Aluminium$ is the most abundant metal, accounting for approximately $8.1\%$ of the earth's crust by weight. $Iron$ is the second most abundant metal, making up about $5.0\%$ of the crust. Therefore, the correct answer is $Aluminium$.

(B) Mercury $(Hg)$ is the metal used in thermometers.
It is a liquid at room temperature and has a high coefficient of thermal expansion,which allows it to expand and contract uniformly with temperature changes.
Additionally,it has a high boiling point and does not stick to the glass walls of the thermometer,making it ideal for measuring temperature accurately.

(D) To determine which metal is the lightest, we compare their densities:
$1$. Copper $(Cu)$: Density $\approx 8.96 \, g/cm^3$
$2$. Silver $(Ag)$: Density $\approx 10.49 \, g/cm^3$
$3$. Lead $(Pb)$: Density $\approx 11.34 \, g/cm^3$
$4$. Magnesium $(Mg)$: Density $\approx 1.74 \, g/cm^3$
Comparing these values, Magnesium has the lowest density among the given options, making it the lightest metal.

(A) Platinum is a noble metal,which means it is highly resistant to corrosion and oxidation. Due to its lustrous appearance,durability,and malleability,it is widely used in the manufacturing of jewelry. Aluminum,lead,and magnesium are not typically used for jewelry because they are either too reactive,too soft,or lack the aesthetic appeal required for fine jewelry.

(B) Most metals are solids at room temperature. However, $\text{Mercury}$ $(Hg)$ is a unique metal that exists in a liquid state at room temperature. Sodium is a soft solid, Magnesium is a solid, and Lead is a solid metal.

(C) semiconductor is a material that has electrical conductivity between that of a conductor (like copper) and an insulator (like glass).
Germanium $(Ge)$ is a well-known metalloid that acts as a semiconductor.
Aluminium,Magnesium,and Lead are metals that act as good conductors of electricity.
Therefore,the correct option is $C$.

(B) Metalloids are elements that possess properties intermediate between those of metals and non-metals.
Common metalloids include Boron $(B)$,Silicon $(Si)$,Germanium $(Ge)$,Arsenic $(As)$,Antimony $(Sb)$,and Tellurium $(Te)$.
Tin $(Sn)$ is a chemical element with atomic number $50$ and is classified as a post-transition metal,not a metalloid.
Therefore,Tin is the correct answer.

(D) Most metals are solid at room temperature. However,there are exceptions.
$1$. Mercury $(Hg)$ is a metal that is liquid at room temperature.
$2$. Gallium $(Ga)$ and Caesium $(Cs)$ have very low melting points ($29.76 \ ^\circ C$ and $28.44 \ ^\circ C$ respectively),which means they can melt in the palm of a human hand.
Among the given options,Gallium is the metal that exists in a liquid state near room temperature.

(B) Most metals are hard,but alkali metals like $Sodium$ $(Na)$ and $Potassium$ $(K)$ are exceptions.
These metals have low density and low melting points.
Due to their weak metallic bonding,they are soft enough to be cut easily with a knife.

(C) Density is defined as mass per unit volume $(d = m/V)$.
Comparing the densities of the given metals:
$1$. Lead $(Pb)$: $\approx 11.34 \ g/cm^3$
$2$. Tin $(Sn)$: $\approx 7.31 \ g/cm^3$
$3$. Aluminium $(Al)$: $\approx 2.70 \ g/cm^3$
$4$. Mercury $(Hg)$: $\approx 13.53 \ g/cm^3$
Among the given options,Aluminium has the lowest density,making it the lightest metal relative to its volume.

(D) Metals are generally good conductors of heat and electricity. However,$Lead$ $(Pb)$ and $Mercury$ $(Hg)$ are known to be comparatively poor conductors of heat and electricity among metals. Therefore,among the given options,$Lead$ is the correct answer.

(C) The property of a metal by which it can be beaten into thin sheets is known as malleability.
Gold and silver are the most malleable metals.
Silver is commonly used to make very thin foils,often used for decorative purposes in food items (like silver leaf or 'vark').
Therefore,silver is the correct answer.

(C) The only non-metal that exists in a liquid state at room temperature is $Bromine$ $(Br)$.
$Carbon$, $Hydrogen$, and $Phosphorus$ are typically found as solids or gases under standard conditions.

(D) In the periodic table,elements are broadly classified into metals,non-metals,and metalloids.
Out of the $114$ elements discovered,$22$ elements are classified as non-metals.
These elements do not exhibit metallic properties such as luster,malleability,ductility,or high electrical conductivity.
Therefore,the correct answer is $22$.

(A) At room temperature,most non-metals are either solids or gases.
Among the given options,$Chlorine$ $(Cl_2)$ is a non-metal that exists as a gas.
$Sulfur$ and $Phosphorus$ are solids at room temperature.
$Bromine$ is a non-metal that exists as a liquid at room temperature.
Therefore,the correct option is $A$.

(C) Non-metals can exist in solid,liquid,or gaseous states at room temperature.
$1$. Bromine $(Br_2)$ is the only non-metal that exists in a liquid state at room temperature.
$2$. Chlorine $(Cl_2)$ and Hydrogen $(H_2)$ exist in a gaseous state at room temperature.
$3$. Sulfur $(S_8)$ is a non-metal that exists in a solid state at room temperature.
Therefore,the correct option is $C$.

(A) Phosphorus is a non-metal that exists in a solid state at room temperature. It is commonly found in different allotropic forms such as white phosphorus and red phosphorus,both of which are solids.

(D) Generally,non-metals are non-lustrous and appear dull. However,$Iodine$ is an exception among non-metals as it possesses a characteristic metallic luster. Therefore,the correct option is $D$.

(B) Most non-metals are poor conductors of electricity because they lack free electrons.
However,$Graphite$,an allotrope of carbon,contains free electrons in its structure due to its hexagonal layered arrangement.
These free electrons allow $Graphite$ to conduct electricity,making it an exception among non-metals.