Final answer:
Helium (He) will have the largest ionization energy due to its position at the top right of its group on the periodic table, indicating it has a full valence shell making it very stable and resistant to losing an electron.
Step-by-step explanation:
To predict which element has the largest ionization energy out of the given options (Hydrogen (H), Helium (He), Francium (Fr), Radon (Rn), and Rhodium (Rh)), we must look at trends on the periodic table. Ionization energy refers to the energy required to remove an electron from the ground state of an atom or ion. It typically increases from left to right across a period and from the bottom to the top of a group in the periodic table.
When comparing the elements provided, Helium (He) sits at the top right of the group except for compared to other noble gases which are in the same column but lower rows. Given that Helium is a noble gas, it has a full valence shell, which makes it very stable and resistant to losing an electron. Hydrogen, while at the top of the periodic table, is only in the first period and thus has a lower ionization energy than Helium. Francium (Fr) and Radon (Rn) are both in lower periods and to the left in their respective groups compared to Helium. Lastly, Rhodium (Rh) is to the right of Francium and Radon but in a lower period compared to Helium.
Considering these trends, we can conclude that Helium (He) will have the highest ionization energy, due to its position in the top right of the group of elements we are considering (excluding other noble gases which are not listed).