MCQ
If an atom has electronic configuration $1{s^2}2{s^2}2{p^6}3{s^2}3{p^6}3{d^3}4{s^2},$ it will be placed in
- ASecond group
- BThird group
- ✓Fifth group
- DSixth group
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$A = - 0.250\,V$ $B = - 0.136\,V$ $C = - 0.126\,V$ $D = - 0.402\,V$
The element that displaces $A$ from its compounds is

$(I)$ the highest oxidation state of iron is $+ 6$ in $K_ 2FeO_4$
$(II)$ that the iron shows $+ 2$ oxidation state with six electrons in the $3d$ orbitals
$(III)$ the common oxidation state of iron is $+3$ with five unpaired electrons in $3d$ orbital
