Which element from the following exhibits various different oxidation states from $+2$ to $+7$?

Which of the following elements is not considered a transition element?

Assertion : Cuprous ion $(Cu^+)$ has unpaired electrons while cupric ion $(Cu^{2+})$ does not.
Reason : Cuprous ion $(Cu^+)$ is colourless whereas cupric ion $(Cu^{2+})$ is blue in the aqueous solution.

How is the variability in oxidation states of transition metals different from that of the non-transition metals? Illustrate with examples.

The element having the electronic configuration $[Kr] 4d^{10} 4f^{14} 5s^2 5p^6 5d^2 6s^2$ belongs to:

Which of the following statements are correct about $Zn$,$Cd$ and $Hg$?
$(I)$ They exhibit high enthalpies of atomisation as the $d-$subshell is full.
$(II)$ $Zn$ and $Cd$ do not show variable oxidation states while $Hg$ shows $+I$ and $+II$.
$(III)$ Compounds of $Zn$,$Cd$ and $Hg$ are paramagnetic in nature.
$(IV)$ $Zn$,$Cd$ and $Hg$ are called soft metals.