-For F-block elements we are mainly focusing on two groups which is...

-Lanathanides 

        &

-Actinides

- They call them inner Transition metals.

-For Lanthanides they are  all silvery-white metals.

-For Actinides they are man made metals except Uranium and Thorium

-Both Lanthanides and Actinides are highly reactive with elements in Halogens

-None of the Actinides have a stable isotopes. They are all radioactive.