The valence shell electronic configuration of $Cr^{2+}$ ion is

Which of the following $3d$ bivalent metal ions has the smallest number of unpaired $d$ electrons?

Which of the following is ferromagnetic?

Which of the following substances is not paramagnetic?

Consider $|x|$ as the difference in oxidation states of Mn in the highest manganese fluoride and the highest manganese oxide. The ions with $|x|$ number of unpaired electrons from the following are: $A$. $Sc^{3+}$ $B$. $Zn^{2+}$ $C$. $V^{2+}$ $D$. $Fe^{2+}$ $E$. $Co^{2+}$ Choose the correct answer from the options given below:

Which among the following cations will not form coloured compounds? (Atomic number $Cu=29, Ti=22, V=23, Mn=25$)