The \( \mathrm{Eu^{2+}} \) ion is a strong reducing agent in spite of its ground state electronic configuration (outermost) : [Atomic number of Eu = \( 63 \)]
\( 4f^7 \)
\( 4f^7 6s^2 \)
\( 4f^6 6s^2 \)
\( 4f^6 \)
