Classification of Elements and Periodicity: JEE Mains Previous Year Questions (2018 - 2024) | Chemistry for JEE Main & Advanced PDF Download

 Page 1


JEE Mains Previous Year Questions 
(2021-2024): Classification of Elements 
and Periodicity in Properties 
2024 
Q1: The transition metal having highest ?? rd 
 ionisation enthalpy is : 
A. ???? 
B. ???? 
C. ???? 
D. ??  [JEE Main 2024 (Online) 1st February Evening Shift] 
Ans: (a) 
The third ionization enthalpy refers to the energy required to remove the third electron from a di-
positive ion (?? 2+
) to form a tripositive ion (?? 3+
). In the case of transition metals, the energies 
involved in removing the third electron are typically higher than for the first and second electrons due to 
an increasing effective nuclear charge and the electrons being removed from closer energy levels to the 
nucleus or from a half-filled or full-filled d-subshell which is relatively more stable. 
Let us look at the electronic configurations of the ions of each metal listed to determine which would 
require the highest third ionisation enthalpy. Since we are talking about 3
rd 
 ionization, we would be 
considering the removal of three electrons, ending up with a +3 oxidation state for each metal. 
Manganese (Mn): [Ar] 3?? 5
4?? 2
 
Iron (Fe): [Ar] 3?? 6
4?? 2
 
Chromium (Cr): [Ar] 3?? 5
4?? 1
 
Vanadium (V): [Ar] 3?? 3
4?? 2
 
After removing two electrons (assuming they come from the 4 s orbital and the next available ?? orbital), 
the configurations would be: 
Mn
2+
:[Ar]3?? 5
 
Fe
2+
:[Ar]3?? 6
 
Cr
2+
:[Ar]3?? 4
 
?? 2+
:[Ar]3?? 3
 
Now we look at the energy required to remove the third electron from the ?? 2+
 ions: 
Page 2


JEE Mains Previous Year Questions 
(2021-2024): Classification of Elements 
and Periodicity in Properties 
2024 
Q1: The transition metal having highest ?? rd 
 ionisation enthalpy is : 
A. ???? 
B. ???? 
C. ???? 
D. ??  [JEE Main 2024 (Online) 1st February Evening Shift] 
Ans: (a) 
The third ionization enthalpy refers to the energy required to remove the third electron from a di-
positive ion (?? 2+
) to form a tripositive ion (?? 3+
). In the case of transition metals, the energies 
involved in removing the third electron are typically higher than for the first and second electrons due to 
an increasing effective nuclear charge and the electrons being removed from closer energy levels to the 
nucleus or from a half-filled or full-filled d-subshell which is relatively more stable. 
Let us look at the electronic configurations of the ions of each metal listed to determine which would 
require the highest third ionisation enthalpy. Since we are talking about 3
rd 
 ionization, we would be 
considering the removal of three electrons, ending up with a +3 oxidation state for each metal. 
Manganese (Mn): [Ar] 3?? 5
4?? 2
 
Iron (Fe): [Ar] 3?? 6
4?? 2
 
Chromium (Cr): [Ar] 3?? 5
4?? 1
 
Vanadium (V): [Ar] 3?? 3
4?? 2
 
After removing two electrons (assuming they come from the 4 s orbital and the next available ?? orbital), 
the configurations would be: 
Mn
2+
:[Ar]3?? 5
 
Fe
2+
:[Ar]3?? 6
 
Cr
2+
:[Ar]3?? 4
 
?? 2+
:[Ar]3?? 3
 
Now we look at the energy required to remove the third electron from the ?? 2+
 ions: 
Mn
2+
:[Ar]3?? 5
Fe
2+
:[Ar]3?? 6
Cr
2+
:[Ar]3?? 4
?? 2+
:[Ar]3?? 3
 
Now we look at the energy required to remove the third electron from the ?? 2+
 ions: 
For Mn
2+
, removing the third electron would break the half-filled 3?? 5
 configuration and require 
significant energy. For Fe
2+
, removing the third electron would form half-filled 3?? 5
 configuration, which 
forms stable configuration. 
For Cr
2+
, the third electron removal will disrupt the 3?? 4
 configuration, which is not particularly stable. 
For ?? 2+
, the third electron removal will disrupt the 3?? 3
 configuration. 
In terms of stability, the half-filled ?? 5
 subshell in manganese (Mn
2+
) provide extra stability. So, the 3
rd 
 
ionisation enthalpy of Mn
2+
 is the highest because it involves breaking a half-filled configuration which 
is more stable. 
Thus, out of the given options, manganese (Mn) would have the highest third ionization enthalpy. 
Therefore, the correct answer is: 
Option A: Mn 
Q2: Given below are two statements: 
Statement (I) : Both metals and non-metals exist in p and d-block elements. 
Statement (II) : Non-metals have higher ionisation enthalpy and higher electronegativity than the 
metals. 
In the light of the above statements, choose the most appropriate answer from the options given 
below: 
A. Both Statement I and Statement II are false 
B. Both Statement I and Statement II are true 
C. Statement I is false but Statement II is true 
D. Statement I is true but Statement II is false   [JEE Main 2024 (Online) 1st February Evening Shift] 
Ans: (c) 
To answer this question, let's investigate both statements in detail. 
Statement (I): Both metals and non-metals exist in p and d-block elements. 
The periodic table is divided into blocks based on the electron configuration of the elements. These 
blocks are labeled s, p, d, and ?? . The ?? -block contains a mix of metals, non-metals, and metalloids. For 
example, the p-block contains nonmetals such as oxygen ( 0 ) and nitrogen ( ?? ), as well as metals like 
aluminum (Al) and lead (Pb). 
The d-block, also known as the transition metals block, primarily consists of metals. However, the d-
block does not typically contain elements that are traditionally classified as non-metals. The elements in 
the d-block have a wide range of properties but are generally characterized by their metallic traits such 
as conductivity and malleability. 
Therefore, Statement I is not entirely true because while both metals and nonmetals exist in the p-block 
of the periodic table, the d-block is principally composed of metals. 
Page 3


JEE Mains Previous Year Questions 
(2021-2024): Classification of Elements 
and Periodicity in Properties 
2024 
Q1: The transition metal having highest ?? rd 
 ionisation enthalpy is : 
A. ???? 
B. ???? 
C. ???? 
D. ??  [JEE Main 2024 (Online) 1st February Evening Shift] 
Ans: (a) 
The third ionization enthalpy refers to the energy required to remove the third electron from a di-
positive ion (?? 2+
) to form a tripositive ion (?? 3+
). In the case of transition metals, the energies 
involved in removing the third electron are typically higher than for the first and second electrons due to 
an increasing effective nuclear charge and the electrons being removed from closer energy levels to the 
nucleus or from a half-filled or full-filled d-subshell which is relatively more stable. 
Let us look at the electronic configurations of the ions of each metal listed to determine which would 
require the highest third ionisation enthalpy. Since we are talking about 3
rd 
 ionization, we would be 
considering the removal of three electrons, ending up with a +3 oxidation state for each metal. 
Manganese (Mn): [Ar] 3?? 5
4?? 2
 
Iron (Fe): [Ar] 3?? 6
4?? 2
 
Chromium (Cr): [Ar] 3?? 5
4?? 1
 
Vanadium (V): [Ar] 3?? 3
4?? 2
 
After removing two electrons (assuming they come from the 4 s orbital and the next available ?? orbital), 
the configurations would be: 
Mn
2+
:[Ar]3?? 5
 
Fe
2+
:[Ar]3?? 6
 
Cr
2+
:[Ar]3?? 4
 
?? 2+
:[Ar]3?? 3
 
Now we look at the energy required to remove the third electron from the ?? 2+
 ions: 
Mn
2+
:[Ar]3?? 5
Fe
2+
:[Ar]3?? 6
Cr
2+
:[Ar]3?? 4
?? 2+
:[Ar]3?? 3
 
Now we look at the energy required to remove the third electron from the ?? 2+
 ions: 
For Mn
2+
, removing the third electron would break the half-filled 3?? 5
 configuration and require 
significant energy. For Fe
2+
, removing the third electron would form half-filled 3?? 5
 configuration, which 
forms stable configuration. 
For Cr
2+
, the third electron removal will disrupt the 3?? 4
 configuration, which is not particularly stable. 
For ?? 2+
, the third electron removal will disrupt the 3?? 3
 configuration. 
In terms of stability, the half-filled ?? 5
 subshell in manganese (Mn
2+
) provide extra stability. So, the 3
rd 
 
ionisation enthalpy of Mn
2+
 is the highest because it involves breaking a half-filled configuration which 
is more stable. 
Thus, out of the given options, manganese (Mn) would have the highest third ionization enthalpy. 
Therefore, the correct answer is: 
Option A: Mn 
Q2: Given below are two statements: 
Statement (I) : Both metals and non-metals exist in p and d-block elements. 
Statement (II) : Non-metals have higher ionisation enthalpy and higher electronegativity than the 
metals. 
In the light of the above statements, choose the most appropriate answer from the options given 
below: 
A. Both Statement I and Statement II are false 
B. Both Statement I and Statement II are true 
C. Statement I is false but Statement II is true 
D. Statement I is true but Statement II is false   [JEE Main 2024 (Online) 1st February Evening Shift] 
Ans: (c) 
To answer this question, let's investigate both statements in detail. 
Statement (I): Both metals and non-metals exist in p and d-block elements. 
The periodic table is divided into blocks based on the electron configuration of the elements. These 
blocks are labeled s, p, d, and ?? . The ?? -block contains a mix of metals, non-metals, and metalloids. For 
example, the p-block contains nonmetals such as oxygen ( 0 ) and nitrogen ( ?? ), as well as metals like 
aluminum (Al) and lead (Pb). 
The d-block, also known as the transition metals block, primarily consists of metals. However, the d-
block does not typically contain elements that are traditionally classified as non-metals. The elements in 
the d-block have a wide range of properties but are generally characterized by their metallic traits such 
as conductivity and malleability. 
Therefore, Statement I is not entirely true because while both metals and nonmetals exist in the p-block 
of the periodic table, the d-block is principally composed of metals. 
Statement (II): Non-metals have higher ionisation enthalpy and higher electronegativity than the metals. 
Ionization enthalpy (or ionization energy) is the energy required to remove an electron from a gaseous 
atom or ion. Non-metals generally have higher ionization energies compared to metals because non-
metals have more tightly bound electrons to their nucleus. This is partly due to the fact that non-metals 
tend to have higher electronegativities and smaller atomic radii, meaning that their outer electrons are 
closer to the nucleus and more strongly attracted to it. 
Electronegativity is a measure of an atom's ability to attract and bond with electrons. Non-metals have 
higher electronegativities typically because they are more eager to gain electrons to achieve a full 
valence shell, reflecting their position on the right side of the periodic table. Metals, on the other hand, 
are more inclined to lose electrons and form positive ions, indicating their lower electronegativities. 
Hence, Statement II is true as non-metals indeed have higher ionisation enthalpy and higher 
electronegativity than metals. 
Given the analysis: 
Statement I is not true. 
Statement II is true. 
Thus, the most appropriate answer is: 
Option C - Statement I is false but Statement II is true. 
Q3: Consider the following elements. 
 
Which of the following is/are true about ?? '
,?? '
,?? '
 and ?? '
 ? 
A. Order of atomic radii: ?? '
<?? '
<?? '
<?? '
 
B. Order of metallic character: ?? '
<?? '
<?? '
<?? '
 
C. Size of the element: ?? '
<?? '
<?? '
<?? '
 
D. Order of ionic radii: ?? '+
<?? ?? +
<?? '+
<?? +
 
Choose the correct answer from the options given below: 
A. A only 
B. B, C and D only 
C. A and B only 
D. A, B and D only     [JEE Main 2024 (Online) 31st January Evening Shift] 
Ans: (d) 
In general along the period from left to right, size decreases and metallic character decrease. 
In general down the group, size increases and metallic character increases. 
Page 4


JEE Mains Previous Year Questions 
(2021-2024): Classification of Elements 
and Periodicity in Properties 
2024 
Q1: The transition metal having highest ?? rd 
 ionisation enthalpy is : 
A. ???? 
B. ???? 
C. ???? 
D. ??  [JEE Main 2024 (Online) 1st February Evening Shift] 
Ans: (a) 
The third ionization enthalpy refers to the energy required to remove the third electron from a di-
positive ion (?? 2+
) to form a tripositive ion (?? 3+
). In the case of transition metals, the energies 
involved in removing the third electron are typically higher than for the first and second electrons due to 
an increasing effective nuclear charge and the electrons being removed from closer energy levels to the 
nucleus or from a half-filled or full-filled d-subshell which is relatively more stable. 
Let us look at the electronic configurations of the ions of each metal listed to determine which would 
require the highest third ionisation enthalpy. Since we are talking about 3
rd 
 ionization, we would be 
considering the removal of three electrons, ending up with a +3 oxidation state for each metal. 
Manganese (Mn): [Ar] 3?? 5
4?? 2
 
Iron (Fe): [Ar] 3?? 6
4?? 2
 
Chromium (Cr): [Ar] 3?? 5
4?? 1
 
Vanadium (V): [Ar] 3?? 3
4?? 2
 
After removing two electrons (assuming they come from the 4 s orbital and the next available ?? orbital), 
the configurations would be: 
Mn
2+
:[Ar]3?? 5
 
Fe
2+
:[Ar]3?? 6
 
Cr
2+
:[Ar]3?? 4
 
?? 2+
:[Ar]3?? 3
 
Now we look at the energy required to remove the third electron from the ?? 2+
 ions: 
Mn
2+
:[Ar]3?? 5
Fe
2+
:[Ar]3?? 6
Cr
2+
:[Ar]3?? 4
?? 2+
:[Ar]3?? 3
 
Now we look at the energy required to remove the third electron from the ?? 2+
 ions: 
For Mn
2+
, removing the third electron would break the half-filled 3?? 5
 configuration and require 
significant energy. For Fe
2+
, removing the third electron would form half-filled 3?? 5
 configuration, which 
forms stable configuration. 
For Cr
2+
, the third electron removal will disrupt the 3?? 4
 configuration, which is not particularly stable. 
For ?? 2+
, the third electron removal will disrupt the 3?? 3
 configuration. 
In terms of stability, the half-filled ?? 5
 subshell in manganese (Mn
2+
) provide extra stability. So, the 3
rd 
 
ionisation enthalpy of Mn
2+
 is the highest because it involves breaking a half-filled configuration which 
is more stable. 
Thus, out of the given options, manganese (Mn) would have the highest third ionization enthalpy. 
Therefore, the correct answer is: 
Option A: Mn 
Q2: Given below are two statements: 
Statement (I) : Both metals and non-metals exist in p and d-block elements. 
Statement (II) : Non-metals have higher ionisation enthalpy and higher electronegativity than the 
metals. 
In the light of the above statements, choose the most appropriate answer from the options given 
below: 
A. Both Statement I and Statement II are false 
B. Both Statement I and Statement II are true 
C. Statement I is false but Statement II is true 
D. Statement I is true but Statement II is false   [JEE Main 2024 (Online) 1st February Evening Shift] 
Ans: (c) 
To answer this question, let's investigate both statements in detail. 
Statement (I): Both metals and non-metals exist in p and d-block elements. 
The periodic table is divided into blocks based on the electron configuration of the elements. These 
blocks are labeled s, p, d, and ?? . The ?? -block contains a mix of metals, non-metals, and metalloids. For 
example, the p-block contains nonmetals such as oxygen ( 0 ) and nitrogen ( ?? ), as well as metals like 
aluminum (Al) and lead (Pb). 
The d-block, also known as the transition metals block, primarily consists of metals. However, the d-
block does not typically contain elements that are traditionally classified as non-metals. The elements in 
the d-block have a wide range of properties but are generally characterized by their metallic traits such 
as conductivity and malleability. 
Therefore, Statement I is not entirely true because while both metals and nonmetals exist in the p-block 
of the periodic table, the d-block is principally composed of metals. 
Statement (II): Non-metals have higher ionisation enthalpy and higher electronegativity than the metals. 
Ionization enthalpy (or ionization energy) is the energy required to remove an electron from a gaseous 
atom or ion. Non-metals generally have higher ionization energies compared to metals because non-
metals have more tightly bound electrons to their nucleus. This is partly due to the fact that non-metals 
tend to have higher electronegativities and smaller atomic radii, meaning that their outer electrons are 
closer to the nucleus and more strongly attracted to it. 
Electronegativity is a measure of an atom's ability to attract and bond with electrons. Non-metals have 
higher electronegativities typically because they are more eager to gain electrons to achieve a full 
valence shell, reflecting their position on the right side of the periodic table. Metals, on the other hand, 
are more inclined to lose electrons and form positive ions, indicating their lower electronegativities. 
Hence, Statement II is true as non-metals indeed have higher ionisation enthalpy and higher 
electronegativity than metals. 
Given the analysis: 
Statement I is not true. 
Statement II is true. 
Thus, the most appropriate answer is: 
Option C - Statement I is false but Statement II is true. 
Q3: Consider the following elements. 
 
Which of the following is/are true about ?? '
,?? '
,?? '
 and ?? '
 ? 
A. Order of atomic radii: ?? '
<?? '
<?? '
<?? '
 
B. Order of metallic character: ?? '
<?? '
<?? '
<?? '
 
C. Size of the element: ?? '
<?? '
<?? '
<?? '
 
D. Order of ionic radii: ?? '+
<?? ?? +
<?? '+
<?? +
 
Choose the correct answer from the options given below: 
A. A only 
B. B, C and D only 
C. A and B only 
D. A, B and D only     [JEE Main 2024 (Online) 31st January Evening Shift] 
Ans: (d) 
In general along the period from left to right, size decreases and metallic character decrease. 
In general down the group, size increases and metallic character increases. 
B
'
<A
'
( size ) C
'
>A
'
( size )
D
'
<C
'
( size ) D
'
>B
'
( size )
B
'
<A
'
( metallic character )
D
'
<C
'
( metallic character )
B
'+
<A
'+
( size )
D
'+
<C
'+
( size )
 
? C statement is incorrect. 
Q4: The correct sequence of electron gain enthalpy of the elements listed below is 
A. Ar 
B. Br 
C. F 
D. S 
Choose the most appropriate from the options given below: 
A. ?? >?? >?? >?? 
B. A > D > B > C 
C. D > C > B > A 
D. C > B > D > A    [JEE Main 2024 (Online) 31st January Morning Shift] 
Ans: (b) 
Element ?
eg 
H(kJ/mol) 
F -333 
 S -200 
Br -325 
Ar +96 
Q5: Given below are two statements: One is labelled as Assertion A and the other is labelled as 
Reason R: 
Assertion ?? : ?? ?? ???? is more acidic than ?? ?? ?? . 
Reason R: Bond dissociation enthalpy of ?? ?? ???? is lower than ?? ?? ?? . 
In the light of the above statements, choose the most appropriate from the options given below: 
A. Both ?? and ?? are true and ?? is the correct explanation of ?? . 
B. Both ?? and ?? are true but ?? is NOT the correct explanation of ?? . 
C. ?? is false but ?? is true. 
D. ?? is true but ?? is false.    [JEE Main 2024 (Online) 30th January Evening Shift] 
Ans: (a) 
Due to lower Bond dissociation enthalpy of H
2
Te it ionizes to give H
+
more easily than H
2
 S. 
Q6: Given below are two statements: 
Statement - I: Along the period, the chemical reactivity of the elements gradually increases from 
group 1 to group 18 . 
Statement - II: The nature of oxides formed by group 1 elements is basic while that of group 17 
elements is acidic. 
In the light of the above statements, choose the most appropriate from the options given below: 
A. Statement ?? is False but statement ?? is true 
B. Both Statement I and Statement II are False 
Page 5


JEE Mains Previous Year Questions 
(2021-2024): Classification of Elements 
and Periodicity in Properties 
2024 
Q1: The transition metal having highest ?? rd 
 ionisation enthalpy is : 
A. ???? 
B. ???? 
C. ???? 
D. ??  [JEE Main 2024 (Online) 1st February Evening Shift] 
Ans: (a) 
The third ionization enthalpy refers to the energy required to remove the third electron from a di-
positive ion (?? 2+
) to form a tripositive ion (?? 3+
). In the case of transition metals, the energies 
involved in removing the third electron are typically higher than for the first and second electrons due to 
an increasing effective nuclear charge and the electrons being removed from closer energy levels to the 
nucleus or from a half-filled or full-filled d-subshell which is relatively more stable. 
Let us look at the electronic configurations of the ions of each metal listed to determine which would 
require the highest third ionisation enthalpy. Since we are talking about 3
rd 
 ionization, we would be 
considering the removal of three electrons, ending up with a +3 oxidation state for each metal. 
Manganese (Mn): [Ar] 3?? 5
4?? 2
 
Iron (Fe): [Ar] 3?? 6
4?? 2
 
Chromium (Cr): [Ar] 3?? 5
4?? 1
 
Vanadium (V): [Ar] 3?? 3
4?? 2
 
After removing two electrons (assuming they come from the 4 s orbital and the next available ?? orbital), 
the configurations would be: 
Mn
2+
:[Ar]3?? 5
 
Fe
2+
:[Ar]3?? 6
 
Cr
2+
:[Ar]3?? 4
 
?? 2+
:[Ar]3?? 3
 
Now we look at the energy required to remove the third electron from the ?? 2+
 ions: 
Mn
2+
:[Ar]3?? 5
Fe
2+
:[Ar]3?? 6
Cr
2+
:[Ar]3?? 4
?? 2+
:[Ar]3?? 3
 
Now we look at the energy required to remove the third electron from the ?? 2+
 ions: 
For Mn
2+
, removing the third electron would break the half-filled 3?? 5
 configuration and require 
significant energy. For Fe
2+
, removing the third electron would form half-filled 3?? 5
 configuration, which 
forms stable configuration. 
For Cr
2+
, the third electron removal will disrupt the 3?? 4
 configuration, which is not particularly stable. 
For ?? 2+
, the third electron removal will disrupt the 3?? 3
 configuration. 
In terms of stability, the half-filled ?? 5
 subshell in manganese (Mn
2+
) provide extra stability. So, the 3
rd 
 
ionisation enthalpy of Mn
2+
 is the highest because it involves breaking a half-filled configuration which 
is more stable. 
Thus, out of the given options, manganese (Mn) would have the highest third ionization enthalpy. 
Therefore, the correct answer is: 
Option A: Mn 
Q2: Given below are two statements: 
Statement (I) : Both metals and non-metals exist in p and d-block elements. 
Statement (II) : Non-metals have higher ionisation enthalpy and higher electronegativity than the 
metals. 
In the light of the above statements, choose the most appropriate answer from the options given 
below: 
A. Both Statement I and Statement II are false 
B. Both Statement I and Statement II are true 
C. Statement I is false but Statement II is true 
D. Statement I is true but Statement II is false   [JEE Main 2024 (Online) 1st February Evening Shift] 
Ans: (c) 
To answer this question, let's investigate both statements in detail. 
Statement (I): Both metals and non-metals exist in p and d-block elements. 
The periodic table is divided into blocks based on the electron configuration of the elements. These 
blocks are labeled s, p, d, and ?? . The ?? -block contains a mix of metals, non-metals, and metalloids. For 
example, the p-block contains nonmetals such as oxygen ( 0 ) and nitrogen ( ?? ), as well as metals like 
aluminum (Al) and lead (Pb). 
The d-block, also known as the transition metals block, primarily consists of metals. However, the d-
block does not typically contain elements that are traditionally classified as non-metals. The elements in 
the d-block have a wide range of properties but are generally characterized by their metallic traits such 
as conductivity and malleability. 
Therefore, Statement I is not entirely true because while both metals and nonmetals exist in the p-block 
of the periodic table, the d-block is principally composed of metals. 
Statement (II): Non-metals have higher ionisation enthalpy and higher electronegativity than the metals. 
Ionization enthalpy (or ionization energy) is the energy required to remove an electron from a gaseous 
atom or ion. Non-metals generally have higher ionization energies compared to metals because non-
metals have more tightly bound electrons to their nucleus. This is partly due to the fact that non-metals 
tend to have higher electronegativities and smaller atomic radii, meaning that their outer electrons are 
closer to the nucleus and more strongly attracted to it. 
Electronegativity is a measure of an atom's ability to attract and bond with electrons. Non-metals have 
higher electronegativities typically because they are more eager to gain electrons to achieve a full 
valence shell, reflecting their position on the right side of the periodic table. Metals, on the other hand, 
are more inclined to lose electrons and form positive ions, indicating their lower electronegativities. 
Hence, Statement II is true as non-metals indeed have higher ionisation enthalpy and higher 
electronegativity than metals. 
Given the analysis: 
Statement I is not true. 
Statement II is true. 
Thus, the most appropriate answer is: 
Option C - Statement I is false but Statement II is true. 
Q3: Consider the following elements. 
 
Which of the following is/are true about ?? '
,?? '
,?? '
 and ?? '
 ? 
A. Order of atomic radii: ?? '
<?? '
<?? '
<?? '
 
B. Order of metallic character: ?? '
<?? '
<?? '
<?? '
 
C. Size of the element: ?? '
<?? '
<?? '
<?? '
 
D. Order of ionic radii: ?? '+
<?? ?? +
<?? '+
<?? +
 
Choose the correct answer from the options given below: 
A. A only 
B. B, C and D only 
C. A and B only 
D. A, B and D only     [JEE Main 2024 (Online) 31st January Evening Shift] 
Ans: (d) 
In general along the period from left to right, size decreases and metallic character decrease. 
In general down the group, size increases and metallic character increases. 
B
'
<A
'
( size ) C
'
>A
'
( size )
D
'
<C
'
( size ) D
'
>B
'
( size )
B
'
<A
'
( metallic character )
D
'
<C
'
( metallic character )
B
'+
<A
'+
( size )
D
'+
<C
'+
( size )
 
? C statement is incorrect. 
Q4: The correct sequence of electron gain enthalpy of the elements listed below is 
A. Ar 
B. Br 
C. F 
D. S 
Choose the most appropriate from the options given below: 
A. ?? >?? >?? >?? 
B. A > D > B > C 
C. D > C > B > A 
D. C > B > D > A    [JEE Main 2024 (Online) 31st January Morning Shift] 
Ans: (b) 
Element ?
eg 
H(kJ/mol) 
F -333 
 S -200 
Br -325 
Ar +96 
Q5: Given below are two statements: One is labelled as Assertion A and the other is labelled as 
Reason R: 
Assertion ?? : ?? ?? ???? is more acidic than ?? ?? ?? . 
Reason R: Bond dissociation enthalpy of ?? ?? ???? is lower than ?? ?? ?? . 
In the light of the above statements, choose the most appropriate from the options given below: 
A. Both ?? and ?? are true and ?? is the correct explanation of ?? . 
B. Both ?? and ?? are true but ?? is NOT the correct explanation of ?? . 
C. ?? is false but ?? is true. 
D. ?? is true but ?? is false.    [JEE Main 2024 (Online) 30th January Evening Shift] 
Ans: (a) 
Due to lower Bond dissociation enthalpy of H
2
Te it ionizes to give H
+
more easily than H
2
 S. 
Q6: Given below are two statements: 
Statement - I: Along the period, the chemical reactivity of the elements gradually increases from 
group 1 to group 18 . 
Statement - II: The nature of oxides formed by group 1 elements is basic while that of group 17 
elements is acidic. 
In the light of the above statements, choose the most appropriate from the options given below: 
A. Statement ?? is False but statement ?? is true 
B. Both Statement I and Statement II are False 
C. Statement I is True But Statement II is False 
D. Both Statement I and Statement II are True   [JEE Main 2024 (Online) 30th January Evening Shift] 
Ans: (a) 
Chemical reactivity of elements decreases along the period therefore statement - I is false. 
Group - 1 elements from basic nature oxides while group - 17 elements form acidic oxides therefore 
statement - II is true. 
Q7: Match List I with List II. 
 
List I 
Species 
 
 
List II 
Electronic distribution 
 
(A) ????
+?? (I) ?? ?? ?? 
(B) ????
+
 (II) ?? ?? ?? ?? ?? ?? 
(C) ????
+?? (III) ?? ?? ?? 
(D) ?? +
 (IV) ?? ?? ?? ?? ?? ?? 
Choose the correct answer from the options given below: 
A. (A)-(III), (B)-(IV), (C)-(I), (D)-(II) 
B. (A)-(I), (B)-(II), (C)-(III), (D)-(IV) 
C. (A)-(IV), (B)-(III), (C)-(I), (D)-(II) 
D. (A)-(II), (B)-(I), (C)-(IV), (D)-(III) [ JEE Main 2024 (Online) 30th January Morning Shift] 
Ans: (a) 
 
24
Cr?[Ar]3 d
5
4 s
1
;Cr
2+
?[Ar]3 d
4
 
25
Mn?[Ar]3 d
5
4 s
2
;Mn
+
?[Ar]3 d
5
4 s
1
 
28
Ni?[Ar]3 d
8
4 s
2
;Ni
2+
?[Ar]3 d
8
 
23
 V?[Ar]3 d
3
4 s
2
;V
+
?[Ar]3 d
3
4 s
1
 
Q8: Given below are two statements: 
Statement I : Fluorine has most negative electron gain enthalpy in its group. 
Statement II : Oxygen has least negative electron gain enthalpy in its group. 
In the light of the above statements, choose the most appropriate from the options given below 
A. Both Statement I and Statement II are true 
B. Both Statement I and Statement II are false 
C. Statement I is false but Statement II is true 
D. Statement I is true but Statement II is false   [JEE Main 2024 (Online) 29th January Evening Shift] 
Ans: (c) 
Statement- 1 is false because chlorine has most negative electron gain enthalpy in its group. 
Q9: The element having the highest first ionization enthalpy is 
A. ?? 
B. ???? 
C. ???? 
D. ??   [JEE Main 2024 (Online) 29th January Evening Shift]