Question

Based on the periodic trends for ionization energy, which element has the highest ionization energy?

Q: Answer-Based on the periodic trends for ionization energy, which element has the highest ionization energy?

Based on periodic trends, helium He has the highest ionization energy. This is because ionization energy generally increases across a period from left to right and decreases down a group. Helium, being in the top-right corner of the periodic table, has a small atomic size and a high effective nuclear charge, leading to a very high ionization energy.