1
JEE Main 2025 (Online) 7th April Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

The number of valence electrons present in the metal among $\mathrm{Cr}, \mathrm{Co}, \mathrm{Fe}$ and Ni which has the lowest enthalpy of atomisation is :

A
10
B
6
C
9
D
8
2
JEE Main 2025 (Online) 7th April Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

The group 14 elements $A$ and $B$ have the first ionisation enthalpy values of 708 and $715 \mathrm{~kJ} \mathrm{~mol}^{-1}$ respectively. The above values are lowest among their group members. The nature of their ions $\mathrm{A}^{2+}$ and $\mathrm{B}^{4+}$ respectively is

A
both reducing
B
oxidising and reducing
C
both oxidising
D
reducing and oxidising
3
JEE Main 2025 (Online) 4th April Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

The incorrect relationship in the following pairs in relation to ionisation enthalpies is :

A
$\mathrm{Mn}^{2+}<\mathrm{Fe}^{2+}$
B
$\mathrm{Mn}^{+}<\mathrm{Mn}^{2+}$
C
$\mathrm{Mn}^{+}<\mathrm{Cr}^{+}$
D
$\mathrm{Fe}^{2+}<\mathrm{Fe}^{3+}$
4
JEE Main 2025 (Online) 4th April Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

The elements of Group 13 with highest and lowest first ionisation enthalpies are respectively :

A
$\mathrm{B} ~\&~ \mathrm{Tl}$
B
$\mathrm{Tl} ~\& ~\mathrm{~B}$
C
$B ~\& ~\operatorname{In}$
D
$B ~\& ~G a$
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