The conversation between human and AI assistant.
Why is ionisation energy of tin less than that of lead?
Can you give me an example of how the shielding effect can affect ionisation energy?
Sure! The shielding effect refers to the ability of inner electrons to block the attraction between the positively charged nucleus and the valence electrons. Elements in the same group of the periodic table have the same number of valence electrons, thus similar ionisation energy. However, due to differences in the number of inner electrons, ionisation energy may vary. For instance, nitrogen has a higher ionisation energy compared to oxygen because the extra electron in oxygen can be shielded by the two additional inner electrons.