Which of the following elements has the highest number of unpaired electrons in its ground state?

Which of the following pairs of ions are colored in their aqueous solution?

Cerium $(IV)$ has a noble gas configuration. Which of the following is the correct statement about it?

Why are the $d$-block elements known as "Transition" elements? Why are zinc,cadmium,and mercury not considered transition elements?

Higher second ionisation enthalpies than expected are observed for

Number of paramagnetic ions among the following $d$- and $f$-block metal ions is . . . . . . . $Mn^{2+}$, $Cu^{2+}$, $Zn^{2+}$, $Yb^{2+}$, $Sc^{3+}$, $La^{3+}$, $Gd^{3+}$, $Lu^{3+}$, $Ti^{4+}$, $Ce^{4+}$. (Atomic number of $Mn = 25$, $Cu = 29$, $Zn = 30$, $Yb = 70$, $Sc = 21$, $La = 57$, $Gd = 64$, $Lu = 71$, $Ti = 22$, $Ce = 58$)