[પરમાણુ ક્રમાંક $Eu, \,63;\, Sm ,\, 62 ;\, Tm ,\, 69 ;\, Tb ,\, 65 \text {; Yb, 70; Dy, 66] }$
\(Tb ^{+4} \rightarrow 4 f ^{7}\)
\(Yb \rightarrow 4 f ^{14} 6 s ^{2}\)
\(Yb ^{+2} \rightarrow 4 f ^{14}\)
(આણ્વિય નંબર $Ti = 22, V = 23, Cr = 24, Mn = 25$)