${ }_{23} \mathrm{~V}^{-2} \Rightarrow[\mathrm{Ar}] 3 \mathrm{~d}^3$
${ }_{25} \mathrm{Mn}^{+2} \Rightarrow[\mathrm{Ar}] 3 \mathrm{~d}^5$
${ }_{26} \mathrm{Fe}^{+2} \Rightarrow[\mathrm{Ar}] 3 \mathrm{~d}^0$
(સૌથી બહારની) : [પરમાણ્વિય ક્રમાંક ${Eu}=63$ ]