Why d block elements are called outer transition and f block elements are called inner transition???? Please explain. Thanks a lot

1 Answer
Jul 27, 2017

Well, if you insert the #f# block elements in their proper place, you would have an extended periodic table:


And so, the #f# block elements are "inner" transition elements, being between the #"Sc"# group and the rest of the #d# block. The #d# block is then "outer", as they are on either side of the "inner" transition metals.

The #f# block elements have rather unusual electron configurations, and you probably won't need to know them in your lifetime. Should you ever want to just for fun, I've written a detailed explanation of why there are so many exceptions to their electron configurations.