Question

The pair of ions having same electronic configuration is _____

• A. $Cr^{3 +},Fe^{3 +}$
• B. $Fe^{3 +},Mn^{2 +}$
• C. $Fe^{3 +},Co^{3 +}$
• D. $Sc^{3 +},Cr^{3 +}$

Answer 1

Answer: (B)

$Fe^{3 +},Mn^{2 +}$

Answer 2

: $Cr(24):3d^{5}4s^{1},Cr^{3 +}:3d^{3}$

$Fe(26):3d^{6}4s^{2},Fe^{3 +}:3d^{5}$

$Mn(25):3d^{5}4s^{2},Mn^{2 +}:3d^{5}$

$Co(27):3d^{7}4s^{2},Co^{3 +}:3d^{6}$

$Sc(21):3d^{1}4s^{2},Sc^{3 +}:3d^{0}$

Thus, $Fe^{3 +}$ and $Mn^{2 +}$have same electronic configuration.