Which element is named after the name of a planet?

Transition elements are usually characterised by variable oxidation states,but $Zn$ does not show this property because of:

Technetium,the element below manganese in the Periodic Table,would be expected to have high values for its:
$(I)$ melting point
$(II)$ boiling point
$(III)$ density

When are $d$-block elements considered as transition elements?

Which of the following metals exhibits more than one oxidation state?

Which of the following cations has the lowest spin-only magnetic moment?