The d-block elements are found in the middle of the period table. The d-block elements are called transition metals and have valence electrons in d orbital's. The f-block elements,found in the two rows at the bottom of the periodic table, are called inner transition metals and have valence electrons in the f-orbital's.
This segment let's go ahead and talk about d and f-Block elements. So when I'm saying d and f-Block elements I'm referring to electron configurations and so we know how many valence electrons each of these elements have based on their position in the periodic table.
So d-Block elements are what we call transition metals and f-Block elements are what we called inner transition metals. So transition metals fall here they spend this area of the periodic table, so group 3 through group 12 and f-Block elements or the inner transition metals are down here at the bottom and we call there it's broken into 2 periods the f-Block elements, as the lanthanides series here in period 6 and the actinides series here in period 7 and so you'll see here there's asterisk here at lanthanum which let's you know that this part kind of drops in here and the same thing for the actinide series it let's you know that this is kind of like where it's supposed to fit in.
So you want to recall about electron configurations that for d orbitals maximally you can have 10 valence electrons and for the f orbitals you can have maximally 14 valence electrons.
So basically then the transition metals are any element whose final electron enters the d sub shell and then for an inner transition metal with f orbitals, they have their final electron entering the f sub shell. So the differences in properties among transition metals are based on the ability of an unpaired electron to move into the last valence shell and so basically the more unpaired electrons you have in your d sub shell the harder your metal is going to be and you'll also have increased melting point and boiling point and that's the basics of d and f elements.