Question

Which of the following does not represent the correct order of the properties indicated?

• A. $Ni^{2+} > Cr^{2+} > Fe^{2+} > Mn^{2+} (size)$
• B. $Sc > Ti > Cr > Mn (size)$
• C. $Ni ^{2+}< Co ^{2+}< Fe ^{2+}< Mn ^{2+}$ (unpaired electron)
• D. Fe$^{2+} >Co^{2+} >Ni^{2+} >Cu^{2+}$(unpaired electron)

Answer 1

Answer: (A)

In a period on moving from left to right ionic radii
decreases. So, the order of cationic radii is
Cr$^{2+} > Mn^{2+} > Fe^{2+} > Ni^{2+}$
In Sc > Ti > Cr > Mn (correct order of atomic radii)
$In \, \, Mn^{2+} > \, \, \, \, Ni^{2+} \, \, \, \, < C0^{2+} \, \, \, \, < Fe^{2+}$
$\, \, \, \, \downarrow \, \, \, \, \, \, \, \, \, \, \, \, \, \, \, \, \, \, \downarrow \, \, \, \, \, \, \, \, \, \, \, \, \downarrow \, \, \, \, \, \, \, \, \, \, \, \, \, \, \downarrow $
$\, \, \, \, \, \, Five \, \, \, \, \, \, \, \, \, \, \, \, \, \, \, Two \, \, \, \, \, \, \, \, \, \, Three \, \, \, \, \, \, \, \, Four $
$\, \, \, \, \, unpaired \, \, \, \, \, \, \, \, unpaired \, \, unpaired \, \, unpaired $
$\, \, \, \, \, electrons \, \, \, \, \, \, \, \, electrons \, \, \, \, electrons \, \, electrons $
$In \, \, Fe^{2+} > \, \, \, \, Co^{2+} \, \, \, \, > Ni^{2+} \, \, \, \, > Cu^{2+}$
$\, \, \, \, \,{}^\downarrow_ {4} \, \, \, \, \, \, \, \, \, \, \, \, \, \, \, \, \, \,{}^\downarrow_ {3} \, \, \, \, \, \, \, \, \, \, \, \, \, \,{}^\downarrow_ {2} \, \, \, \, \, \, \, \, \, \, \, \, \, \,{}^\downarrow_ {1} $
Number of unpaired electrons