<P> D - block elements are unified by having in their outermost electrons one or more d - orbital electrons but no p - orbital electrons . The d - orbitals can contain up to five pairs of electrons; hence, the block includes ten columns in the periodic table . </P> <P> The f - block is in the center - left of a 32 - column periodic table but in the footnoted appendage of 18 - column tables . These elements are not generally considered as part of any group . They are often called inner transition metals because they provide a transition between the s - block and d - block in the 6th and 7th row (period), in the same way that the d - block transition metals provide a transitional bridge between the s - block and p - block in the 4th and 5th rows . </P> <P> The known f - block elements come in two series, the lanthanides of period 6 and the radioactive actinides of period 7 . All are metals . Because the f - orbital electrons are less active in determining the chemistry of these elements, their chemical properties are mostly determined by outer s - orbital electrons . Consequently, there is much less chemical variability within the f - block than within the s -, p -, or d - blocks . </P> <P> F - block elements are unified by having one or more of their outermost electrons in the f - orbital but none in the d - orbital or p - orbital . The f - orbitals can contain up to seven pairs of electrons; hence, the block includes fourteen columns in the periodic table . </P>

Where do metals lie on the periodic table