What effect does increased electronic shielding have on ionisation energy?

Increased electronic shielding occurs when the inner electrons within an atom effectively block the outer electrons from the full positive charge of the nucleus. This shielding effect reduces the effective nuclear charge experienced by the outermost electrons. As a result, these outer electrons feel less attraction to the nucleus, making it easier to remove them from the atom.

When it comes to ionisation energy, which is the energy required to remove an electron from an atom, decreased attraction due to increased shielding means that less energy is needed to remove the outer electron. Therefore, as electronic shielding increases, ionisation energy decreases. This principle is important for understanding trends in the periodic table, particularly as you move down a group, where increased numbers of electron shells contribute to enhanced shielding.