6.0 F-Block Elements - Introduction

  d and f Block Elements

• The elements in which last i.e.,differentiating electron is entering in pre-penultimate i.e.,$(n-2)f$ subshell are called $f$-block elements.

• The group of $28$ element having atomic number $58$ to $71$ and $90$ to $103$ are collectively called $f$-block elements.

• Their last two outer subshells are incompletely or partially filled and they are $(n-1)d$ and $(n-2)f$.

• Due to the properties of these elements between electropositive metals and electronegative nonmetals and addition of last electrons relatively at inner position they are called inner transition metals.

• F-Block elements are divided in two series i.e., $4f$ (lanthanoid series) and $5f$ (actinoide series).