Screening Effect

The screening effect refers to the phenomenon where outer electrons in an atom are influenced by the presence of inner electrons, which 'screen' or shield them from the full charge of the atomic nucleus. This means that outer electrons experience a reduced attractive force from the nucleus, making them easier to remove. As a result, the chemical properties of elements can be understood better, particularly their reactivity and ionization energy. In essence, inner electrons affect how strongly the nucleus can hold onto outer electrons, shaping the behavior of the atom in chemical reactions.