What do the elements have in common?

They all have valence electrons in the f-orbitals.-the answer is d. by working out the electronic configurations of some of the elements, you will realize that they all have valence electrons in the f-orbitals. hence the lanthanoids and actinoids are also called the f-block elements.a. not true. some can use their partially-filled f-orbitals to form compounds of variable oxidation states, such as +4, +5 and +6. this is, in fact, similar to the transition metals.b. nope. they are shown separately simply because there is not enough space! On a side note, the g-block elements (uut, uuq, uqp, etc) are hypothetical (undiscovered) elements with their places in the periodic table pre-booked until they are successfully synthesised or discovered.c. some of them are stable and occur naturally.