Question

Why do $Zr$ and $Hf$ have similar properties?

Answer 1

$Zr$ and $Hf$ exhibit similar properties due to lanthanide contraction. Electrons present in $f$-subshell dosen't have good shielding effect due to which with increase in atomic number effective nuclear charge, size gets constricted and thus size of $Hf$ and $Zr$ becomes almost equal and hence both have similar properties.