Electrovalent bonding Questions in English

(D) The correct answer is $(D)$.
In $K_2S$,the compound consists of $K^{+}$ and $S^{2-}$ ions.
The atomic number of $K$ is $19$,so the $K^{+}$ ion has $19 - 1 = 18$ electrons.
The atomic number of $S$ is $16$,so the $S^{2-}$ ion has $16 + 2 = 18$ electrons.
Since both $K^{+}$ and $S^{2-}$ have $18$ electrons,they are isoelectronic.

(A) The reaction between sodium $(Na)$ and chlorine $(Cl_2)$ is highly exothermic,meaning energy is released during the process.
Since $Na$ is a metal and $Cl$ is a non-metal,they transfer electrons to form an ionic bond,resulting in the compound sodium chloride $(NaCl)$.

(C) First,determine the valency of each element based on its electronic configuration:
$L (1s^2, 2s^2 2p^4)$ has $6$ valence electrons,so it gains $2$ electrons to complete its octet. Valency = $-2$.
$Q (1s^2, 2s^2 2p^6, 3s^2 3p^5)$ has $7$ valence electrons,so it gains $1$ electron. Valency = $-1$.
$P (1s^2, 2s^2 2p^6, 3s^1)$ has $1$ valence electron,so it loses $1$ electron. Valency = $+1$.
$R (1s^2, 2s^2 2p^6, 3s^2)$ has $2$ valence electrons,so it loses $2$ electrons. Valency = $+2$.
Combining these to form neutral ionic compounds:
$P (+1)$ and $L (-2)$ form $P_2L$.
$R (+2)$ and $L (-2)$ form $RL$.
$P (+1)$ and $Q (-1)$ form $PQ$.
$R (+2)$ and $Q (-1)$ form $RQ_2$.
Thus,the correct set of formulas is $P_2L, RL, PQ$ and $RQ_2$.

(C) Electrovalent compounds (ionic compounds) consist of ions held together by strong electrostatic forces of attraction.
Due to these strong forces,they have high melting and boiling points.
They are generally soluble in polar solvents like water.
In the solid state,ions are fixed in a lattice and cannot move,but in the fused (molten) or aqueous state,the ions become free to move,allowing them to conduct electricity.
Therefore,the correct property is that they conduct current in the fused state.

(D) An electrovalent compound is formed by the electrostatic attraction between oppositely charged ions.
These ions are electrically charged atoms or groups of atoms.
For example,$NaCl$ is composed of $Na^{+}$ and $Cl^{-}$ ions.
An ionic bond,also known as an electrovalent bond,is formed when valence electrons are permanently transferred from one atom to another.

(D) The formation of an electrovalent (ionic) bond depends on three main energy factors:
$1$. The energy required to form a cation,which is the $Ionization \ Energy$.
$2$. The energy released during the formation of an anion,which is the $Electron \ Affinity$.
$3$. The energy released when the ions pack together to form a crystal lattice,which is the $Lattice \ Energy$.
Therefore,the correct answer is $(d)$.

(C) The formation of $NaCl$ involves the complete transfer of an electron from a sodium atom to a chlorine atom.
This transfer results in the formation of $Na^+$ and $Cl^-$ ions,which are held together by strong electrostatic forces of attraction.
Such a bond is known as an electrovalent or ionic bond.
Therefore,the correct option is $(C)$.

(A) . Electrovalent compounds exhibit high melting and boiling points due to the strong electrostatic forces of attraction between the oppositely charged ions in their crystal lattice.

(D) The lattice energy $(U)$ of an ionic compound is directly proportional to the product of the charges on the ions $(q_1, q_2)$ and inversely proportional to the distance between them $(r_0)$,expressed as $U \propto \frac{|q_1 q_2|}{r_0}$.
Thus,it depends on both the magnitude of the charges on the ions and the ionic radii (size of the ions).

(A) The ionic character of a bond depends on the difference in electronegativity between the bonded atoms.
Greater the difference in electronegativity,higher is the ionic character.
$Cs$ (Cesium) is an alkali metal with the lowest electronegativity among the given elements,while $Cl$ (Chlorine) is a highly electronegative non-metal.
Therefore,the electronegativity difference is maximum for the $Cs-Cl$ bond,making it the most ionic.

(A) Since $x$ is strongly electropositive and univalent,it forms a cation $x^+$.
Since $y$ is strongly electronegative and univalent,it forms an anion $y^-$.
The combination of $x^+$ and $y^-$ results in the formation of an ionic compound with the formula $xy$.

(C) The formation of $NaCl$ involves the transfer of an electron from $Na$ to $Cl$.
$Na \rightarrow Na^+ + e^-$
$Cl + e^- \rightarrow Cl^-$
Thus,$Na$ loses an electron to form a cation,and $Cl$ accepts an electron to form an anion,resulting in an ionic bond.

(B) An electrovalent linkage (or ionic bond) is formed by the complete transfer of electrons from a metal to a non-metal.
In $MgCl_2$,magnesium $(Mg)$ is an electropositive metal that loses two electrons to form $Mg^{2+}$,and chlorine $(Cl)$ is an electronegative non-metal that gains electrons to form $Cl^-$.
Thus,$MgCl_2$ exhibits an electrovalent linkage.
The other compounds ($CH_4$,$SiCl_4$,and $BF_3$) are covalent compounds.

(A) Electrovalent compounds (ionic compounds) are characterized by strong electrostatic forces of attraction between oppositely charged ions.
These strong forces require a large amount of energy to overcome,resulting in high melting points $(M.P.)$ and high boiling points $(B.P.)$.
Therefore,the statement that they have "High $M.P.$ and Low $B.P.$" is incorrect.
Thus,the correct option is $A$.

(C) Element $A$ $(1s^2)$ is Helium,a noble gas,which is chemically inert.
Element $B$ $(1s^2, 2s^2 2p^2)$ has $4$ valence electrons and typically forms covalent bonds.
Element $C$ $(1s^2, 2s^2 2p^5)$ has $7$ valence electrons. It requires $1$ electron to complete its octet,readily forming an anion $(C^-)$,which facilitates the formation of an electrovalent (ionic) bond.
Element $D$ $(1s^2, 2s^2 2p^6)$ is Neon,a noble gas,which is chemically inert.
Therefore,element $C$ is the most likely to form an electrovalent bond.

(D) Sodium chloride $(NaCl)$ is an electrovalent (ionic) compound.
Water is a polar solvent with a high dielectric constant.
When $NaCl$ is added to water,the electrostatic forces of attraction between $Na^+$ and $Cl^-$ ions are overcome by the ion-dipole interactions between the ions and water molecules,leading to the solvation of ions.

(A) Electrovalency is the formation of ionic bonds between atoms.
For the formation of an ionic bond,the metal should easily lose electrons to form a cation,and the non-metal should easily gain electrons to form an anion.
$1$. $A$ large cation is preferred because the valence electrons are further from the nucleus and held less tightly,making them easier to remove.
$2$. $A$ small anion is preferred because the incoming electron is closer to the nucleus,resulting in a stronger attraction.
$3$. $A$ low charge on the ions is favorable because it requires less energy to remove or add electrons.
Therefore,the conditions are: low charge on ions,large cation,and small anion.

(B) Ionic bonds are formed by the transfer of electrons from a metal to a non-metal.
$1$. The metal atom should have a $Low \ ionization \ potential$ to easily lose an electron to form a cation.
$2$. The non-metal atom should have a $High \ electron \ affinity$ to easily accept the electron to form an anion.
Therefore,the correct combination is $Low \ ionization \ potential$ and $High \ electron \ affinity$.

(B) $Cs$ is an alkali metal with low ionization energy,making it highly electropositive.
$F$ is a halogen with high electron affinity,making it highly electronegative.
Due to the large difference in electronegativity,$Cs$ transfers an electron to $F$ to form an ionic bond.

(A) An ionic bond is formed by the electrostatic attraction between oppositely charged ions.
$KCl$ is an ionic compound because it consists of $K^+$ and $Cl^-$ ions held together by strong electrostatic forces.
$CH_4$ (methane) contains covalent bonds between carbon and hydrogen atoms.
Diamond consists of a giant covalent lattice structure where carbon atoms are linked by strong covalent bonds.
$H_2$ is a molecule formed by a covalent bond between two hydrogen atoms.
Therefore,the correct option is $A$.

(B) An electrovalent linkage,also known as an ionic bond,is formed by the complete transfer of electrons from one atom to another.
$Na$ is a highly electropositive alkali metal,and $Cl$ is a highly electronegative halogen.
Therefore,$Na$ transfers an electron to $Cl$ to form $NaCl$,which contains an electrovalent linkage.
Thus,the correct option is $B$.

(A) Metals have low ionization energy,which means they can easily lose their valence electrons to form positive ions (cations) when reacting with non-metals.

(C) The strength of a bond is determined by the nature of the interaction.
$Na-Cl$ is an ionic bond,which involves a strong electrostatic force of attraction between the $Na^+$ and $Cl^-$ ions.
$H-Cl$,$Cl-Cl$,and $C-Cl$ are covalent bonds,which are generally weaker than ionic bonds in the solid state.
Therefore,the $Na-Cl$ bond is the strongest among the given options.

(D) The melting point of ionic compounds depends on the lattice energy. $NaF$ has the maximum melting point among the given sodium halides. As the size of the halide ion increases from $F^-$ to $I^-$,the lattice energy decreases,leading to a decrease in the melting point.

(C) $CaCl_2$ will have electrovalent bonding.
Calcium $(Ca)$ is an electropositive metal,and chlorine $(Cl)$ is an electronegative non-metal.
They combine by the transfer of electrons from calcium to chlorine,resulting in an electrovalent (ionic) bond.

(C) An electrovalent bond,also known as an ionic bond,is formed by the complete transfer of electrons from one atom to another.
This results in the formation of positively charged ions (cations) and negatively charged ions (anions).
The strong force of attraction that holds these oppositely charged ions together in the crystal lattice is the electrostatic force of attraction.

(A) An electrovalent bond (ionic bond) is formed by the complete transfer of electrons from one atom to another.
Since one atom loses electrons (oxidation) and the other atom gains electrons (reduction),the process is a $Redox$ reaction.

(B) Electrovalent compounds are formed by the electrostatic attraction between oppositely charged ions.
Because they consist of ions,they are polar in nature.
Therefore,the correct option is $(b)$.

(C) Ionic compounds are formed by strong electrostatic forces of attraction between oppositely charged ions.
$1$. Hard and brittle: Due to strong electrostatic forces,they are solid and hard. They are brittle because the application of pressure causes like charges to come closer,leading to repulsion and breakage.
$2$. High melting and boiling points: $A$ large amount of energy is required to overcome the strong electrostatic forces of attraction between ions.
$3$. Non-directional nature: Ionic bonds are non-directional because the electrostatic force of attraction acts in all directions around the ion.
$4$. Solubility: They are generally soluble in polar solvents like water due to the hydration energy overcoming the lattice energy.
Therefore,ionic compounds do not possess directional properties,which are characteristic of covalent bonds.

(B) The strength of an ionic bond is directly proportional to the electrostatic force of attraction between the ions. As the electronegativity difference between the bonded atoms increases,the ionic character of the bond increases,which in turn increases the strength of the ionic bond.

(A) The electronegativity difference between the two elements is calculated as: $\Delta EN = 3.0 - 1.2 = 1.8$.
According to the Pauling scale,if the electronegativity difference is greater than $1.7$,the bond is considered to be ionic in nature.
Since $1.8 > 1.7$,the bond formed is ionic.

(A) Ionic character depends on the electronegativity difference between the bonded atoms.
$KCl$ and $BaCl_2$ are typical ionic compounds consisting of metal cations and chloride anions.
$C_6H_5NH_3^+Cl^-$ is an ionic salt (anilinium chloride).
$C_2H_5Cl$ (Ethyl chloride) is an organic compound where the bond between carbon and chlorine is primarily covalent due to the small difference in electronegativity between $C$ and $Cl$.
Therefore,$C_2H_5Cl$ is the least ionic among the given options.

(A) $Li_2O$ is an ionic compound formed by the transfer of electrons from $Li$ to $O$.
$CaF_2$ is an ionic compound formed by the transfer of electrons from $Ca$ to $F$.
Therefore,both compounds exhibit ionic bonding.

(A) The electrostatic force of attraction between a positively charged cation and a negatively charged anion results in the formation of an $Ionic$ bond. Therefore,the correct option is $(A)$.

(A) $KI$ is an ionic compound because it is formed by the transfer of electrons from a metal $(K)$ to a non-metal $(I)$,resulting in a large electronegativity difference between the atoms.

(B) Ionic compounds are characterized by strong electrostatic forces of attraction between oppositely charged ions,which results in high lattice energy.
Because of this strong electrostatic attraction,ionic compounds typically exhibit high melting and boiling points.
They are generally soluble in polar solvents like water due to the hydration energy overcoming the lattice energy,but they are sparingly soluble or insoluble in non-polar organic solvents.
Therefore,the statement that ionic compounds have 'least lattice energy' is incorrect,as they possess high lattice energy.

(A) . Electrolytes are compounds that dissociate into their constituent ions when dissolved in water or in a molten state. These compounds are held together by strong electrostatic forces of attraction,which are characteristic of an electrovalent (or ionic) bond.

(D) Electrovalent compounds (also known as ionic compounds) are formed by strong electrostatic forces of attraction between oppositely charged ions.
These strong forces require a large amount of energy to break,resulting in high melting points and high boiling points compared to covalent compounds.

(D) The electronic configuration of $X$ is $1s^2 2s^2 2p^6 3s^2 3p^6 4s^2$. It has $2$ valence electrons in the $4s$ orbital,so it tends to lose $2$ electrons to achieve a stable noble gas configuration,forming the $X^{2+}$ ion.
The electronic configuration of $Y$ is $1s^2 2s^2 2p^6 3s^2 3p^5$. It has $7$ valence electrons,so it tends to gain $1$ electron to complete its octet,forming the $Y^{-}$ ion.
To form a neutral compound,the charges must balance: $X^{2+} + 2Y^{-} \rightarrow XY_2$.
Thus,$1$ atom of $X$ combines with $2$ atoms of $Y$ to form the compound $XY_2$.

(B) $NH_4Cl$ contains both polar and non-polar bonds.
In the ammonium ion $(NH_4^+)$,the $N-H$ bonds are polar covalent bonds.
The bond between the $NH_4^+$ cation and the $Cl^-$ anion is an ionic bond.
However,the question refers to the presence of polar and non-polar covalent bonds within the structure.
Specifically,in $NH_4Cl$,the $N-H$ bonds are polar covalent,and the interaction between the ions is ionic.
Comparing the options,$NH_4Cl$ is the correct choice as it exhibits both ionic and covalent (polar) characteristics.

(B) The valency of an element is determined by the number of electrons it needs to gain or lose to complete its octet.
Element $A$ has $3$ valence electrons,so it loses $3$ electrons to achieve a stable configuration. Thus,its valency is $3$.
Element $B$ has $6$ valence electrons,so it needs to gain $2$ electrons to complete its octet. Thus,its valency is $2$.
Using the criss-cross method,the formula of the compound formed by $A$ (valency $3$) and $B$ (valency $2$) is $A_2B_3$.

(B) In an ionic (electrovalent) crystal,cations and anions are held together by strong electrostatic forces of attraction.

(D) The correct answer is $(D)$.
In $NaOH$,the bond between $O$ and $H$ is covalent,while the bond between the $Na^+$ cation and the $OH^-$ anion is ionic.

(B) The ionizing power of a solvent is directly proportional to its dielectric constant.
$A$ higher dielectric constant reduces the electrostatic force of attraction between ions in a solute,thereby facilitating their dissociation into ions.
Therefore,an ionizing solvent must have a high dielectric constant.

(D) Ionic compounds are composed of ions held together by strong electrostatic forces of attraction.
Due to these strong forces,they have high melting and boiling points.
They are generally soluble in polar solvents like water and insoluble in non-polar solvents.
In the solid state,ions are fixed in a lattice,but in the fused (molten) or aqueous state,the ions become free to move,allowing them to conduct electricity.
Therefore,the correct statement is that they conduct electricity in the fused state.

(C) An ionic solution is formed by substances that dissociate into ions when dissolved in water.
$NaBr$ is an ionic compound consisting of $Na^+$ and $Br^-$ ions.
When dissolved in water,it undergoes complete dissociation: $NaBr(s) \rightarrow Na^+(aq) + Br^-(aq)$.
$CCl_4$,$O_2$,and $CHBr_3$ are covalent compounds and do not dissociate into ions in water.

(A) Ionic bonds are formed between elements with a large difference in electronegativity.
Group $1$ elements (alkali metals) have the lowest electronegativity,and Group $17$ (often referred to as group $7$ in older notations or representing halogens) elements have the highest electronegativity.
Therefore,the combination of Group $1$ and Group $7$ elements results in the most predominantly ionic compounds.

(B) The formation of an ionic bond depends upon the easy formation of a cation and an anion.
For a metal atom to form a cation easily,it should have low ionisation energy.
For a non-metal atom to form an anion easily,it should have high electron affinity.

(B) The ionic character of a covalent bond is directly proportional to the electronegativity difference between the bonded atoms.
Fluorine $(F)$ is the most electronegative element in the periodic table.
Therefore,the electronegativity difference between $H$ $(2.1)$ and $F$ $(4.0)$ is the highest among the given hydrogen halides,leading to the highest ionic character in $HF$.

(A) The electronegativity difference between the two elements is calculated as: $\Delta EN = 3.0 - 1.2 = 1.8$.
According to the Pauling scale,if the electronegativity difference is greater than $1.7$,the bond formed is predominantly ionic.
Since $1.8 > 1.7$,the bond is ionic.