The electronic configuration of the last element of the volatile metal group is:

Which pair of ions gives a blue colour in an aqueous state?
$V^{+4}, Ni^{+2}, Ti^{+3}, Co^{+2}, Fe^{+3}, Cu^{+2}$

Which of the following weighs less when weighed in a magnetic field?

Given below are two statements:
Statement $I$: Ferromagnetism is considered as an extreme form of paramagnetism.
Statement $II$: The number of unpaired electrons in a $Cr^{2+}$ ion $(Z=24)$ is the same as that of a $Nd^{3+}$ ion $(Z=60)$.
In the light of the above statements,choose the correct answer from the options given below:

Which of the following statements is incorrect?

All transition elements are $d$-block elements,but all $d$-block elements are not transition elements. Explain.