D And F Block Elements Question 1
Question 1 - 2024 (01 Feb Shift 2)
The transition metal having highest $3^{\text {rd }}$ ionisation enthalpy is :
(1) $Cr$
(2) $Mn$
(3) $V$
(4) $Fe$
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Answer (2)
Solution
3rd Ionisation energy : [NCERT Data]
$V: 2833 KJ / mol$
$Cr: 2990 KJ / mol$
$Mn: 3260 KJ / mol$
$Fe: 2962 KJ / mol$
alternative
$Mn: 3 d^{5} 4 s^{2}$
$Fe: 3 d^{6} 4 s^{2}$
Cr : $3 d^{5} 4 s^{1}$
$V: 3 d^{3} 4 s^{2}$
So Mn has highest 3rd IE among all the given elements due to $d^{5}$ configuration.
