Which of the following ions is diamagnetic?

Determine whether the following statements are True $(T)$ or False $(F)$:
$(a)$ Transition elements contain $d$-orbitals.
$(b)$ Ions of transition elements contain incompletely filled $d$-orbitals.
$(c)$ Only elements with completely filled $3d$ orbitals are considered transition elements.
$(d)$ Only elements that have incompletely filled $d$-orbitals in their ground state as well as in their ions are called transition elements.

Which of the following does not represent the property stated against it?

Identify the element for which the electronic configuration in the $+3$ oxidation state is $[Ar] 3d^5$:

Determine whether the following statements are True $(T)$ or False $(F)$:
$(a)$ Transition elements exhibit variable oxidation states.
$(b)$ The $E^o$ values for $Mn, Zn,$ and $Ni$ are more positive than expected from the general trend.
$(c)$ Any metal exhibits its maximum high oxidation state in oxide and chloride compounds.

Determine whether the following statements are True $(T)$ or False $(F)$:
$(a)$ An element or its ion that does not have a completely filled $d$-orbital is considered a transition element.
$(b)$ $Sc$ is a transition element.
$(c)$ $Zn$ is a transition element.
$(d)$ The energy difference between $(n-1)d$ and $ns$ orbitals is high.