Which of the following elements has the highest work function value?

Because of lanthanoid contraction,which of the following pairs of elements have nearly same atomic radii? (Numbers in the parenthesis are atomic numbers)

Which among the following elements does not have any electron in the $f-$subshell in either its expected or observed electronic configuration?

Which of the following ions indicates the maximum magnetic moment?

Which of the following is ferromagnetic?

Explain the variations in atomic radii of transition elements along the period. The following table provides data for the first transition series:

Element	Sc	Ti	$V$	Cr	Mn	Fe	Co	Ni	Cu	Zn
Metallic Radius $M$ (pm)	$164$	$147$	$135$	$129$	$137$	$126$	$125$	$125$	$128$	$137$