Frank Textbook Solutions: Chemical Bonding

 Page 1


Chapter 2. Chemical Bonding
PAGE N0 : 39 
Solution 1: 
Chemical bond: A chemical bond may be defined as the linkage that stands for the force 
which actually holds the atoms together within the molecule. 
Chemical bonding: The phenomenon during which a chemical bond is formed is called 
chemical bonding.
Solution 2: 
Atoms combine to attain the electronic configuration of nearest inert gases as the atoms of 
inert gases are very stable having 8 electrons or duplet (or 2 electrons in case of helium 
atom) in their outermost shell.
Solution 3: 
Electrovalent compounds: The chemical compounds containing electrovalent bonds are 
called electrovalent or ionic compounds. 
For example: Sodium chloride (NaCl). 
Covalent compounds: The chemical compound, formed as a result of mutual sharing of 
electrons or electron pairs thereby establishing a covalent bond is called a covalent or 
molecular compound. 
For example: Hydrogen molecule (H2)
Solution 4: 
The conditions for the formation of an electrovalent bond are:
1. Low ionization energy of electropositive atom
2. High electron affinity of the electronegative atom.
3. Large electronegativity difference.
4. High lattice energy. 
Concept Insight:
 
Lower is the ionization energy of atom, higher is its tendency to lose electron to 
form a cation and form ionic bond.
Higher the value of electron affinity of an atom, greater will be its tendency to 
form anion and form ionic bond.
If the electronegativity difference of two elements is higher, more easy will be 
the transfer of electrons and hence more chances of ionic bond formation.
Lattice energy is the energy released when positive and negatively charged 
atoms called ions come closer to form a crystal because the attractive forces 
among the oppositely charged ions tend to decrease the energy of the system. 
Higher is the lattice energy, greater will be the ease of formation of the 
compound.
 
Page 2


Chapter 2. Chemical Bonding
PAGE N0 : 39 
Solution 1: 
Chemical bond: A chemical bond may be defined as the linkage that stands for the force 
which actually holds the atoms together within the molecule. 
Chemical bonding: The phenomenon during which a chemical bond is formed is called 
chemical bonding.
Solution 2: 
Atoms combine to attain the electronic configuration of nearest inert gases as the atoms of 
inert gases are very stable having 8 electrons or duplet (or 2 electrons in case of helium 
atom) in their outermost shell.
Solution 3: 
Electrovalent compounds: The chemical compounds containing electrovalent bonds are 
called electrovalent or ionic compounds. 
For example: Sodium chloride (NaCl). 
Covalent compounds: The chemical compound, formed as a result of mutual sharing of 
electrons or electron pairs thereby establishing a covalent bond is called a covalent or 
molecular compound. 
For example: Hydrogen molecule (H2)
Solution 4: 
The conditions for the formation of an electrovalent bond are:
1. Low ionization energy of electropositive atom
2. High electron affinity of the electronegative atom.
3. Large electronegativity difference.
4. High lattice energy. 
Concept Insight:
 
Lower is the ionization energy of atom, higher is its tendency to lose electron to 
form a cation and form ionic bond.
Higher the value of electron affinity of an atom, greater will be its tendency to 
form anion and form ionic bond.
If the electronegativity difference of two elements is higher, more easy will be 
the transfer of electrons and hence more chances of ionic bond formation.
Lattice energy is the energy released when positive and negatively charged 
atoms called ions come closer to form a crystal because the attractive forces 
among the oppositely charged ions tend to decrease the energy of the system. 
Higher is the lattice energy, greater will be the ease of formation of the 
compound.
 
Solution 6: 
Hydrogen chloride has a polar covalent bond because in hydrogen chloride the higher 
electronegativity of chlorine atom attracts the shared electron pair towards itself. As a 
result, the chlorine atom gets a partial negative charge while the hydrogen atom gets a 
partial positive charge. Hence such a covalent bond with charge separation is called polar 
covalent bond. 
While methane has a non polar covalent bond because in case of methane molecule the 
shared electron pairs are at equal distance from the carbon and hydrogen atoms, because 
neither the carbon atom nor the hydrogen atom has enough electronegativity difference 
between each other to attract the shared pairs of electrons towards itself. Hence no charge 
separation occurs in the covalent bond due to which it is called non polar covalent bond. 
Concept Insight: When a covalent bond is formed between the atoms of the same 
elements of equal electronegativity then the electron pairs are shared equally between the 
atoms and the bond so formed is called non polar covalent bond. On the other hand, if the 
covalent bond is formed between atoms of different elements, with difference in electro 
negativity, the electrons are not shared equally between the atoms. The more 
electronegative atom pulls the bonded pair of electrons towards itself and acquires 
negative charge while the other less electro negative atom acquires positive charge and 
the bond becomes polar covalent bond.
Solution 7: 
In terms of electron transfer, oxidation is defined as the phenomenon in which an atom 
loses electron to form a positively charged cation while reduction is defined as the 
phenomenon in which an atom gains electron to form a negatively charged ion called 
anion. 
During formation of ionic bond one atom undergoes oxidation while another atom 
undergoes reduction.
 
Solution 5:
Page 3


Chapter 2. Chemical Bonding
PAGE N0 : 39 
Solution 1: 
Chemical bond: A chemical bond may be defined as the linkage that stands for the force 
which actually holds the atoms together within the molecule. 
Chemical bonding: The phenomenon during which a chemical bond is formed is called 
chemical bonding.
Solution 2: 
Atoms combine to attain the electronic configuration of nearest inert gases as the atoms of 
inert gases are very stable having 8 electrons or duplet (or 2 electrons in case of helium 
atom) in their outermost shell.
Solution 3: 
Electrovalent compounds: The chemical compounds containing electrovalent bonds are 
called electrovalent or ionic compounds. 
For example: Sodium chloride (NaCl). 
Covalent compounds: The chemical compound, formed as a result of mutual sharing of 
electrons or electron pairs thereby establishing a covalent bond is called a covalent or 
molecular compound. 
For example: Hydrogen molecule (H2)
Solution 4: 
The conditions for the formation of an electrovalent bond are:
1. Low ionization energy of electropositive atom
2. High electron affinity of the electronegative atom.
3. Large electronegativity difference.
4. High lattice energy. 
Concept Insight:
 
Lower is the ionization energy of atom, higher is its tendency to lose electron to 
form a cation and form ionic bond.
Higher the value of electron affinity of an atom, greater will be its tendency to 
form anion and form ionic bond.
If the electronegativity difference of two elements is higher, more easy will be 
the transfer of electrons and hence more chances of ionic bond formation.
Lattice energy is the energy released when positive and negatively charged 
atoms called ions come closer to form a crystal because the attractive forces 
among the oppositely charged ions tend to decrease the energy of the system. 
Higher is the lattice energy, greater will be the ease of formation of the 
compound.
 
Solution 6: 
Hydrogen chloride has a polar covalent bond because in hydrogen chloride the higher 
electronegativity of chlorine atom attracts the shared electron pair towards itself. As a 
result, the chlorine atom gets a partial negative charge while the hydrogen atom gets a 
partial positive charge. Hence such a covalent bond with charge separation is called polar 
covalent bond. 
While methane has a non polar covalent bond because in case of methane molecule the 
shared electron pairs are at equal distance from the carbon and hydrogen atoms, because 
neither the carbon atom nor the hydrogen atom has enough electronegativity difference 
between each other to attract the shared pairs of electrons towards itself. Hence no charge 
separation occurs in the covalent bond due to which it is called non polar covalent bond. 
Concept Insight: When a covalent bond is formed between the atoms of the same 
elements of equal electronegativity then the electron pairs are shared equally between the 
atoms and the bond so formed is called non polar covalent bond. On the other hand, if the 
covalent bond is formed between atoms of different elements, with difference in electro 
negativity, the electrons are not shared equally between the atoms. The more 
electronegative atom pulls the bonded pair of electrons towards itself and acquires 
negative charge while the other less electro negative atom acquires positive charge and 
the bond becomes polar covalent bond.
Solution 7: 
In terms of electron transfer, oxidation is defined as the phenomenon in which an atom 
loses electron to form a positively charged cation while reduction is defined as the 
phenomenon in which an atom gains electron to form a negatively charged ion called 
anion. 
During formation of ionic bond one atom undergoes oxidation while another atom 
undergoes reduction.
 
Solution 5:
Solution 8: 
PAGE NO : 48
Page 4


Chapter 2. Chemical Bonding
PAGE N0 : 39 
Solution 1: 
Chemical bond: A chemical bond may be defined as the linkage that stands for the force 
which actually holds the atoms together within the molecule. 
Chemical bonding: The phenomenon during which a chemical bond is formed is called 
chemical bonding.
Solution 2: 
Atoms combine to attain the electronic configuration of nearest inert gases as the atoms of 
inert gases are very stable having 8 electrons or duplet (or 2 electrons in case of helium 
atom) in their outermost shell.
Solution 3: 
Electrovalent compounds: The chemical compounds containing electrovalent bonds are 
called electrovalent or ionic compounds. 
For example: Sodium chloride (NaCl). 
Covalent compounds: The chemical compound, formed as a result of mutual sharing of 
electrons or electron pairs thereby establishing a covalent bond is called a covalent or 
molecular compound. 
For example: Hydrogen molecule (H2)
Solution 4: 
The conditions for the formation of an electrovalent bond are:
1. Low ionization energy of electropositive atom
2. High electron affinity of the electronegative atom.
3. Large electronegativity difference.
4. High lattice energy. 
Concept Insight:
 
Lower is the ionization energy of atom, higher is its tendency to lose electron to 
form a cation and form ionic bond.
Higher the value of electron affinity of an atom, greater will be its tendency to 
form anion and form ionic bond.
If the electronegativity difference of two elements is higher, more easy will be 
the transfer of electrons and hence more chances of ionic bond formation.
Lattice energy is the energy released when positive and negatively charged 
atoms called ions come closer to form a crystal because the attractive forces 
among the oppositely charged ions tend to decrease the energy of the system. 
Higher is the lattice energy, greater will be the ease of formation of the 
compound.
 
Solution 6: 
Hydrogen chloride has a polar covalent bond because in hydrogen chloride the higher 
electronegativity of chlorine atom attracts the shared electron pair towards itself. As a 
result, the chlorine atom gets a partial negative charge while the hydrogen atom gets a 
partial positive charge. Hence such a covalent bond with charge separation is called polar 
covalent bond. 
While methane has a non polar covalent bond because in case of methane molecule the 
shared electron pairs are at equal distance from the carbon and hydrogen atoms, because 
neither the carbon atom nor the hydrogen atom has enough electronegativity difference 
between each other to attract the shared pairs of electrons towards itself. Hence no charge 
separation occurs in the covalent bond due to which it is called non polar covalent bond. 
Concept Insight: When a covalent bond is formed between the atoms of the same 
elements of equal electronegativity then the electron pairs are shared equally between the 
atoms and the bond so formed is called non polar covalent bond. On the other hand, if the 
covalent bond is formed between atoms of different elements, with difference in electro 
negativity, the electrons are not shared equally between the atoms. The more 
electronegative atom pulls the bonded pair of electrons towards itself and acquires 
negative charge while the other less electro negative atom acquires positive charge and 
the bond becomes polar covalent bond.
Solution 7: 
In terms of electron transfer, oxidation is defined as the phenomenon in which an atom 
loses electron to form a positively charged cation while reduction is defined as the 
phenomenon in which an atom gains electron to form a negatively charged ion called 
anion. 
During formation of ionic bond one atom undergoes oxidation while another atom 
undergoes reduction.
 
Solution 5:
Solution 8: 
PAGE NO : 48
Solution 9: 
Solution 10:
1. Sodium chloride dissolves in water because it is an ionic compound and water is also 
a polar covalent compound. Water decreases the electrostatic forces of attraction 
among the sodium and chloride ions due to which these ions become free in water, 
hence sodium chloride dissolves. 
On the other hand, carbon tetra chloride has non polar covalent bond and water has 
polar covalent bond. Hence, water is unable to break the non polar covalent bond of 
carbon tetra chloride. So it is insoluble in water
2. Helium does not form He2 molecule as it has its outermost shell complete i.e. two 
electrons in its valence shell. Due to this complete valence shell helium atom is very 
stable hence does not participate in chemical bonding to form He2 molecule.
Page 5


Chapter 2. Chemical Bonding
PAGE N0 : 39 
Solution 1: 
Chemical bond: A chemical bond may be defined as the linkage that stands for the force 
which actually holds the atoms together within the molecule. 
Chemical bonding: The phenomenon during which a chemical bond is formed is called 
chemical bonding.
Solution 2: 
Atoms combine to attain the electronic configuration of nearest inert gases as the atoms of 
inert gases are very stable having 8 electrons or duplet (or 2 electrons in case of helium 
atom) in their outermost shell.
Solution 3: 
Electrovalent compounds: The chemical compounds containing electrovalent bonds are 
called electrovalent or ionic compounds. 
For example: Sodium chloride (NaCl). 
Covalent compounds: The chemical compound, formed as a result of mutual sharing of 
electrons or electron pairs thereby establishing a covalent bond is called a covalent or 
molecular compound. 
For example: Hydrogen molecule (H2)
Solution 4: 
The conditions for the formation of an electrovalent bond are:
1. Low ionization energy of electropositive atom
2. High electron affinity of the electronegative atom.
3. Large electronegativity difference.
4. High lattice energy. 
Concept Insight:
 
Lower is the ionization energy of atom, higher is its tendency to lose electron to 
form a cation and form ionic bond.
Higher the value of electron affinity of an atom, greater will be its tendency to 
form anion and form ionic bond.
If the electronegativity difference of two elements is higher, more easy will be 
the transfer of electrons and hence more chances of ionic bond formation.
Lattice energy is the energy released when positive and negatively charged 
atoms called ions come closer to form a crystal because the attractive forces 
among the oppositely charged ions tend to decrease the energy of the system. 
Higher is the lattice energy, greater will be the ease of formation of the 
compound.
 
Solution 6: 
Hydrogen chloride has a polar covalent bond because in hydrogen chloride the higher 
electronegativity of chlorine atom attracts the shared electron pair towards itself. As a 
result, the chlorine atom gets a partial negative charge while the hydrogen atom gets a 
partial positive charge. Hence such a covalent bond with charge separation is called polar 
covalent bond. 
While methane has a non polar covalent bond because in case of methane molecule the 
shared electron pairs are at equal distance from the carbon and hydrogen atoms, because 
neither the carbon atom nor the hydrogen atom has enough electronegativity difference 
between each other to attract the shared pairs of electrons towards itself. Hence no charge 
separation occurs in the covalent bond due to which it is called non polar covalent bond. 
Concept Insight: When a covalent bond is formed between the atoms of the same 
elements of equal electronegativity then the electron pairs are shared equally between the 
atoms and the bond so formed is called non polar covalent bond. On the other hand, if the 
covalent bond is formed between atoms of different elements, with difference in electro 
negativity, the electrons are not shared equally between the atoms. The more 
electronegative atom pulls the bonded pair of electrons towards itself and acquires 
negative charge while the other less electro negative atom acquires positive charge and 
the bond becomes polar covalent bond.
Solution 7: 
In terms of electron transfer, oxidation is defined as the phenomenon in which an atom 
loses electron to form a positively charged cation while reduction is defined as the 
phenomenon in which an atom gains electron to form a negatively charged ion called 
anion. 
During formation of ionic bond one atom undergoes oxidation while another atom 
undergoes reduction.
 
Solution 5:
Solution 8: 
PAGE NO : 48
Solution 9: 
Solution 10:
1. Sodium chloride dissolves in water because it is an ionic compound and water is also 
a polar covalent compound. Water decreases the electrostatic forces of attraction 
among the sodium and chloride ions due to which these ions become free in water, 
hence sodium chloride dissolves. 
On the other hand, carbon tetra chloride has non polar covalent bond and water has 
polar covalent bond. Hence, water is unable to break the non polar covalent bond of 
carbon tetra chloride. So it is insoluble in water
2. Helium does not form He2 molecule as it has its outermost shell complete i.e. two 
electrons in its valence shell. Due to this complete valence shell helium atom is very 
stable hence does not participate in chemical bonding to form He2 molecule.
3. Pure water does not conduct electricity because it has a polar covalent molecule 
hence does not have ions in it which can conduct electricity. 
On adding sodium chloride to pure water, sodium chloride breaks apart into sodium 
and chloride ions because water being polar decreases the strong forces of attraction 
among sodium and chloride ions. Now, pure water has ions present in it which can 
conduct electricity.
4. Cl2 is a non polar molecule because the bond is between same atoms that is chlorine 
with zero electronegativity difference among them. So the shared electron pair is 
attracted equally by the two chlorine atoms hence there is no separation of charges 
in the bond formed so the chlorine molecule is non polar.
5. In case of HCl the bond is formed between two different atoms that is hydrogen and 
chlorine with enough electro negativity difference so that the shared electron pair is 
attracted towards more electronegative chlorine atom which acquires partial negative 
charge while the hydrogen atom acquires partial positive charge hence HCl is a polar 
molecule.
6. Metals have low ionization energy due to which they can lose their outermost 
electrons easily to form positive metallic ions hence metals are electropositive. 
For example Sodium metal always form Na
+
ions, Potassium forms K
+ 
ions etc.
Solution 11:
1. (i) when the electro negativity difference between the two atoms is high then the 
bond formed will be purely ionic. 
(ii) When the electro negativity difference between the two atoms is low then the 
bond formed will be polar covalent bond. 
(iii) When the electro negativity difference between the two atoms is zero then the 
bond formed will be purely covalent.
2. Ionic compounds = NO, NH
4
Cl, NH
4
NO
3
 
Covalent compounds = N2, NH2 , NO 
Polar compounds = NCl3
Concept Insight: Electro negativity difference between the bonded atoms determines the 
ease of transfer of electrons between the atoms. On the basis of extent of transfer of 
electrons between the two atoms the bond will be ionic, covalent or polar.