$d$-block elements form

Consider the hydrated ions of $Ti^{2+}$,$V^{2+}$,$Ti^{3+}$,and $Sc^{3+}$. The correct order of their spin-only magnetic moments is

Which of the following statements concern with transition metals?

Which of the following ions are diamagnetic?

The electronic configuration of $Gd^{2+}$ is (at. no. of $Gd$ is $64$)

Most transition metals exhibit several characteristic properties. Which of the following statements are correct?
$I$: Form sets of compounds which display different oxidation states of the metal.
$II$: Form coloured ions in solution.
$III$: Burn vigorously in oxygen.
$IV$: Act as catalysts.