Reaction of Metals and Non-metals (Ionic Compounds) Questions in English

(N/A) $(i)$ The representation of elements with valence electrons as dots around the element symbol is referred to as the electron-dot structure.
$(a)$ Sodium $(2, 8, 1) = Na^{\bullet}$
$(b)$ Oxygen $(2, 6) = :\ddot{O}:$
$(c)$ Magnesium $(2, 8, 2) = Mg^{\bullet\bullet}$
$(ii)$ Formation of $Na_{2}O$:
$2Na^{\bullet} + :\ddot{O}: \rightarrow (Na^{+})_{2}[:\ddot{O}:]^{2-}$
Formation of $MgO$:
$Mg^{\bullet\bullet} + :\ddot{O}: \rightarrow (Mg^{2+})[:\ddot{O}:]^{2-}$
$(iii)$ The ions present in $Na_{2}O$ are $Na^{+}$ and $O^{2-}$ ions,and in $MgO$ are $Mg^{2+}$ and $O^{2-}$ ions.

(N/A) Ionic compounds are formed by the transfer of electrons between atoms,resulting in the formation of positively charged cations and negatively charged anions.
These oppositely charged ions are held together by strong electrostatic forces of attraction.
To melt an ionic compound,a significant amount of energy is required to overcome these strong inter-ionic forces.
Consequently,ionic compounds exhibit high melting points.

(B) The element is likely to be calcium $(Ca)$.
Calcium reacts with oxygen to form calcium oxide $(CaO)$,which is an ionic compound.
Ionic compounds typically have high melting points due to strong electrostatic forces of attraction between ions.
Calcium oxide $(CaO)$ reacts with water to form calcium hydroxide $(Ca(OH)_2)$,which is soluble in water.

(D) The formula $XCl_2$ indicates that the element $X$ has a valency of $2$ (since chlorine has a valency of $1$). Elements that form chlorides with the formula $XCl_2$ are typically alkaline earth metals belonging to Group $2$ of the Periodic Table. Among the given options,$Mg$ (Magnesium) belongs to Group $2$. Therefore,$X$ would most likely be in the same group as $Mg$.

(A) Ionic compounds are formed by the transfer of electrons from a metal to a non-metal, resulting in strong electrostatic forces of attraction between ions.
$(i)$ $KCl$ ($\text{Potassium}$ $\text{Chloride}$) is an ionic compound because it consists of $K^+$ and $Cl^-$ ions.
$(ii)$ $HCl$ ($\text{Hydrogen}$ $\text{Chloride}$) is a covalent compound because it is formed by the sharing of electrons between $H$ and $Cl$ atoms.
$(iii)$ $CCl_4$ ($\text{Carbon}$ $\text{Tetrachloride}$) is a covalent compound because it is formed by the sharing of electrons between $C$ and $Cl$ atoms.
$(iv)$ $NaCl$ ($\text{Sodium}$ $\text{Chloride}$) is an ionic compound because it consists of $Na^+$ and $Cl^-$ ions.
Therefore, $(ii)$ and $(iii)$ are not ionic compounds.

(B) Ionic compounds are formed by the strong electrostatic force of attraction between oppositely charged ions.
In the solid state,these ions are held in a rigid crystal lattice structure and are not free to move.
Therefore,ionic compounds do not conduct electricity in the solid state.
However,when dissolved in water or in a molten state,the crystal lattice breaks down,allowing the ions to move freely,which enables them to conduct electricity.
Additionally,ionic compounds generally have high melting and boiling points due to the strong inter-ionic forces and are typically soluble in water.

(C) In an electrolytic cell,electrical energy is converted into chemical energy.
By definition,the electrode connected to the positive terminal of the battery is the anode,which is positively charged.
The electrode connected to the negative terminal of the battery is the cathode,which is negatively charged.
Therefore,an electrolytic cell consists of a positively charged anode $(iii)$ and a negatively charged cathode $(iv)$.

(A) When $X$ loses an electron and $Y$ gains an electron,an ionic bond is formed between them,resulting in an ionic compound $Z$.
Ionic compounds are characterized by strong electrostatic forces of attraction between oppositely charged ions.
Due to these strong forces,ionic compounds typically have high melting and boiling points.
They exist as solids at room temperature and are generally hard.
They conduct electricity when dissolved in water or in a molten state because the ions become free to move.
Therefore,the property 'Has low melting point' is not shown by ionic compound $Z$.

(A) To determine the formula of a binary compound,we balance the valencies of the combining elements:
$(a)$ $Mg$ has a valency of $+2$ and $N$ has a valency of $-3$. By criss-crossing the valencies,we get $Mg_{3}N_{2}$ (Magnesium nitride).
$(b)$ $Li$ has a valency of $+1$ and $O$ has a valency of $-2$. By criss-crossing the valencies,we get $Li_{2}O$ (Lithium oxide).
$(c)$ $Al$ has a valency of $+3$ and $Cl$ has a valency of $-1$. By criss-crossing the valencies,we get $AlCl_{3}$ (Aluminium chloride).
$(d)$ $K$ has a valency of $+1$ and $O$ has a valency of $-2$. By criss-crossing the valencies,we get $K_{2}O$ (Potassium oxide).

(N/A) $1$. Identification of elements: Element $A$ has atomic number $19$, which is Potassium $(K)$. Its electronic configuration is $2, 8, 8, 1$. Element $B$ has atomic number $17$, which is Chlorine $(Cl)$. Its electronic configuration is $2, 8, 7$.
$2$. Formation of the product: Element $A$ loses $1$ electron to achieve a stable octet, forming $A^+$ ion. Element $B$ gains $1$ electron to achieve a stable octet, forming $B^-$ ion. The formula of the product is $AB$ (Potassium Chloride, $KCl$).
$3$. Electronic dot structure: $A \cdot + \cdot \dot{B} \cdot \rightarrow [A]^+ [:\ddot{B}:]^-$.
$4$. Nature of the bond: Since the bond is formed by the complete transfer of electrons from a metal to a non-metal, it is an ionic bond.

(A-D) The electronic configuration of element $X$ $(Z=17)$ is $2, 8, 7$. Since it has $7$ valence electrons,it belongs to Group $17$ and the $3^{rd}$ period.
The electronic configuration of element $Y$ $(Z=20)$ is $2, 8, 8, 2$. Since it has $2$ valence electrons,it belongs to Group $2$ and the $4^{th}$ period.
$(b)$ Element $X$ is a non-metal because it gains electrons to complete its octet. Element $Y$ is a metal because it loses $2$ electrons to form a stable cation.

(N/A) Element $Y$ has an atomic number of $20$,which corresponds to Calcium $(Ca)$. Its electronic configuration is $2, 8, 8, 2$. Since it is a metal,its oxide ($YO$ or $CaO$) will be basic in nature.
The compound formed is $YX_2$ $(CaCl_2)$. Since $Y$ is a metal and $X$ is a non-metal (Chlorine,atomic number $17$),the bonding between them is ionic.
$(b)$ The electron dot structure involves the transfer of two electrons from the outermost shell of $Y$ to two atoms of $X$:
$Y_{\times}^{\times} + 2[\cdot X : ] \rightarrow [Y^{2+} (\times \cdot X : ^{-})_2]$

(C) Ionic compounds consist of ions held together by strong electrostatic forces of attraction in a rigid crystal lattice.
In the solid state,these ions are fixed in their positions and are not free to move.
Since the conduction of electricity requires the movement of charged particles (ions),ionic compounds cannot conduct electricity in the solid state.
They only conduct electricity when molten or dissolved in water,as the ions become free to move in these states.

(N/A) The atomic number of magnesium $(Mg)$ is $12$, and its electronic configuration is $2, 8, 2$. It has $2$ valence electrons.
The atomic number of chlorine $(Cl)$ is $17$, and its electronic configuration is $2, 8, 7$. It has $7$ valence electrons.
To form magnesium chloride $(MgCl_2)$, the magnesium atom loses $2$ electrons to achieve a stable octet configuration, forming a $Mg^{2+}$ ion.
Each of the two chlorine atoms gains $1$ electron from the magnesium atom to complete their octets, forming two $Cl^-$ ions.
The electron dot structure and transfer process are as follows:
$Mg: + 2 \cdot \ddot{Cl}: \rightarrow [Mg^{2+}] [: \ddot{Cl}:^-]_2$

(A) Sodium chloride $(NaCl)$ is an ionic compound consisting of $Na^+$ and $Cl^-$ ions held together by strong electrostatic forces of attraction.
Water is a polar solvent with a high dielectric constant,which helps in overcoming the electrostatic forces of attraction between the ions,allowing $NaCl$ to dissociate and dissolve.
Conversely,kerosene is a non-polar organic solvent.
It lacks the ability to provide the necessary energy to break the strong ionic bonds in $NaCl$,and therefore,$NaCl$ remains insoluble in it.

(IONIC BOND) The bond formed by the transfer of electrons from a metal to a non-metal is an $Ionic$ bond.
The general properties of ionic compounds are:
$(i)$ They are usually crystalline solids due to strong electrostatic forces of attraction.
$(ii)$ They have high melting and boiling points.
$(iii)$ They are generally soluble in water but insoluble in organic solvents like kerosene or petrol.
$(iv)$ They conduct electricity in their molten state or in aqueous solution because the ions become free to move.

(N/A) Ionic compounds are formed by the transfer of electrons between atoms,resulting in the formation of positively charged cations and negatively charged anions.
These oppositely charged ions are held together by very strong electrostatic forces of attraction.
Because of these strong inter-ionic forces,a significant amount of energy is required to break the crystal lattice and overcome these forces,which results in high melting and boiling points.

(N/A) $(i)$ Due to the strong electrostatic force of attraction between the oppositely charged ions,ionic compounds exist as solids. They are generally brittle and break into pieces when pressure is applied.
$(ii)$ Ionic compounds are generally soluble in water because the polar water molecules break the ionic bonds.
$(iii)$ Ionic compounds do not conduct electricity in the solid state because the ions are held in a fixed lattice. However,they conduct electricity in the aqueous or molten state because the ions become free to move.

(N/A) Formation of $MgO$:
$Mg (2, 8, 2) \to Mg^{2+} + 2e^-$
$O (2, 6) + 2e^- \to O^{2-}$
$Mg^{2+} + O^{2-} \to MgO$
$(b)$ $(i)$ Cation: Magnesium ion $(Mg^{2+})$.
$(ii)$ Anion: Oxide ion $(O^{2-})$.
$(c)$ Properties of ionic compounds:
$(i)$ They are generally crystalline solids and are soluble in water.
$(ii)$ They have high melting and boiling points due to strong electrostatic forces of attraction.
$(iii)$ They conduct electricity in the molten state or in aqueous solution because the ions are free to move.

(N/A) $(i)$ Ionic compounds have high melting and boiling points because a considerable amount of energy is required to break the strong inter-ionic electrostatic forces of attraction.
$(ii)$ Ionic compounds are soluble in water because the polar water molecules interact with the ions,overcoming the lattice energy and causing them to dissociate.
$(iii)$ They are solids and somewhat hard because of the strong electrostatic force of attraction between the oppositely charged ions,which holds them in a rigid crystal lattice structure.
$(iv)$ Ionic compounds conduct electricity in the molten state because the heat overcomes the electrostatic forces,allowing the ions to become free to move and carry charge.
$(v)$ Metals have a tendency to lose electrons to attain a stable,completely filled valence shell configuration (noble gas configuration).

(A) Elements that form anions are those that gain electrons to complete their valence shell. Among the given elements,$O$ (Oxygen),$F$ (Fluorine),and $Cl$ (Chlorine) are non-metals that gain electrons to form anions.
$(b)$ The electronic configurations of the identified anions are:
$O^{2-}$ (Oxide ion): Atomic number $8$,configuration $2, 6$. By gaining $2$ electrons,it becomes $2, 8$.
$F^{-}$ (Fluoride ion): Atomic number $9$,configuration $2, 7$. By gaining $1$ electron,it becomes $2, 8$.
$Cl^{-}$ (Chloride ion): Atomic number $17$,configuration $2, 8, 7$. By gaining $1$ electron,it becomes $2, 8, 8$.

(A-D) $Cl$ and $O$ are non-metals with high electronegativity and will gain electrons to form anions ($Cl^-$ and $O^{2-}$).
$Na$ and $Al$ are metals with low ionization energy and will lose electrons to form cations ($Na^+$ and $Al^{3+}$).
$(b)$ Inert elements are those that have a stable valence shell configuration (octet or duplet) and do not react under normal conditions. Examples include $He$ (Helium) and $Ne$ (Neon).

(II, V) Oxygen $(O)$ and chlorine $(Cl)$ would form anions.
$O + 2e^- \rightarrow O^{2-}$ (Oxide ion)
$Cl + e^- \rightarrow Cl^-$ (Chloride ion)
Reason: Anions are negatively charged ions formed by the gain of electrons. Non-metals like oxygen and chlorine gain electrons to achieve a stable noble gas electronic configuration (octet rule).

(C) Electronic configuration:

Element	$K$	$L$	$M$
$X_{11}$	$2$	$8$	$1$
$Y_{16}$	$2$	$8$	$6$

$(b)$ They will form an ionic bond.
Reason: $X$ has $1$ valence electron and will lose it to form $X^+$ ion. $Y$ has $6$ valence electrons and will gain $2$ electrons to form $Y^{2-}$ ion. The bond formed by the transfer of valence electrons from a metal $(X)$ to a non-metal $(Y)$ is called an ionic or electrovalent bond.
$(c)$ Formula of the compound:

Symbol	Valency
$X$	$+1$
$Y$	$-2$

By criss-cross method,the formula is $X_2Y$.

(N/A) Electron-dot structure of sodium: $Na \cdot$
Electron-dot structure of chlorine atom: $: \ddot{Cl} \cdot$
Sodium $(Na)$ has $1$ valence electron. It loses this electron to attain the stable electronic configuration of the nearest noble gas,neon $(Ne)$.
Chlorine $(Cl)$ has $7$ valence electrons. It gains the electron lost by sodium to complete its octet and achieve the stable electronic configuration of the nearest noble gas,argon $(Ar)$.
The electrostatic force of attraction between the positively charged sodium ion $(Na^+)$ and the negatively charged chloride ion $(Cl^-)$ results in the formation of an ionic bond (also called an electrovalent bond).
Compounds formed by ionic bonds have high melting points because a large amount of energy is required to break the strong electrostatic forces of attraction between the oppositely charged ions.

(D) In an electrolytic cell,electrical energy is used to drive a non-spontaneous chemical reaction.
By definition,the electrode where reduction occurs is the cathode,and in an electrolytic cell,the cathode is connected to the negative terminal of the external power source,making it negatively charged.
The electrode where oxidation occurs is the anode,and in an electrolytic cell,the anode is connected to the positive terminal of the external power source,making it positively charged.
Therefore,the correct characteristics are $(iii)$ Positively charged anode and $(iv)$ Negatively charged cathode.

(C) Ionic compounds are formed by the electrostatic attraction between oppositely charged ions.
In the solid state,these ions are held in a rigid crystal lattice structure and are not free to move.
Because electrical conductivity requires the movement of charged particles,ionic compounds do not conduct electricity in the solid state.
However,when dissolved in water or in a molten state,the crystal lattice breaks down,allowing the ions to move freely,which enables them to conduct electricity.
Therefore,the property not exhibited by ionic compounds is electrical conductivity in the solid state.

(TRUE) True.
Ionic compounds are composed of ions (cations and anions) held together by strong electrostatic forces of attraction.
When an ionic compound is dissolved in water,these forces are weakened,allowing the ions to become free to move.
When electricity is passed through this aqueous solution,the cations (positively charged ions) move towards the cathode (negatively charged electrode) and the anions (negatively charged ions) move towards the anode (positively charged electrode),thereby conducting electricity.

(C) Alumina $(Al_2O_3)$ is a very stable oxide of aluminum.
It has a very high melting point due to the strong ionic bonds between aluminum and oxygen atoms in its crystal lattice.
The melting point of pure alumina is approximately $2348\;K$ $(2075\;^{\circ}C)$.
Therefore,option $C$ is the correct answer.

(C) Ammonia $(NH_3)$ is a chemical substance composed of nitrogen and hydrogen atoms in a fixed ratio of $1:3$.
Since it is formed by the chemical combination of two different elements,it is classified as a compound.
Elements are pure substances consisting of only one type of atom,whereas mixtures are physical combinations of substances without fixed proportions.
Therefore,ammonia is a compound.

(C) Phosphorus pentoxide is a chemical compound with the empirical formula $P_{2}O_{5}$.
However,in its solid state,it exists as a dimer with the molecular formula $P_{4}O_{10}$.
While $P_{2}O_{5}$ is often used to represent the empirical formula,$P_{4}O_{10}$ is the correct molecular formula for the substance as it exists in nature.