Why do the d, f orbitals of transition metals have less reactivity?

[MophiA]

Thinking about filling sequence 5s -> 4d or 6s -> 4f, the n=4 orbitals are way smaller than n=5 or 6.

Does this mean "localized"?

Even though the n=4 orbitals are way smaller, close to nucleus, these orbitals have more energy than n=5, 6 orbitals above.

What makes it less reactive?

 

[adf89812]

less reactive compared to what?