Which one of the following is paramagnetic?

Which of the following compounds is expected to be coloured?

In which of the following pairs,both the elements do not have $(n-1)d^{10} ns^2$ configuration?

The number of $4f$ electrons in the ground state electronic configuration of $Gd^{2+}$ is ........ .
[Atomic number of $Gd=64$]

Given below are two statements: one is labelled as Assertion $A$ and the other is labelled as Reason $R$.
Assertion $A$: Generally, $3d$ transition metals have high melting points.
Reason $R$: Involvement of $3d$-electrons in addition to $4s$-electrons in the interatomic metallic bonding.
In light of the above statements, choose the most appropriate answer from the options given below:

The $3d-$ elements show variable oxidation states. What is the maximum oxidation state shown by the element $Mn$?