Identify the element that has a ground state electronic configuration of [kr]5s24d5.

Elements in their ground state are neutral, so the number of electrons they have is equivalent to the number of protons. The electrons in this element are:
36 (from Kr) + 2 in the 5s orbital + 5 in the 4d orbital
= 43 electrons

So the protons must also be 43. Looking at the periodic table at atomic number 43, we see that this element is Technetium

30litre of li2o is 1.0002mole approximately 1 mole