The shielding effect is best described as

The shielding effect is best described as

• A. The shielding effect is the increase in attraction between the nucleus and outer electrons.
• B. The shielding effect is the decrease in attraction between the nucleus and outer electrons due to inner electrons.
• C. The shielding effect is the energy released when an electron is removed.
• D. The shielding effect is the attraction between electrons outside the atom.

Answer: (B)

Shielding effect refers to inner electrons partially blocking the attraction of the nucleus for the outer electrons, so the outer electrons feel a smaller effective nuclear charge. In atoms with more electrons, the inner shells repel and shield some of the positive pull of the nucleus, reducing the net attraction that outer electrons experience. This effective nuclear charge, often written as Z_eff = Z − S, helps explain why outer electrons are less tightly bound and how trends in the periodic table arise: shielding increases down a group (more inner shells), while across a period shielding stays relatively constant but Z increases, raising Z_eff and ionization energy. The described concept best matches the reduced attraction due to inner electrons. The other descriptions don’t fit: shielding is not an increase in nucleus–outer-electron attraction, it’s not about the energy released when an electron is removed, and it’s not about attraction between electrons outside the atom.

Shielding effect refers to inner electrons partially blocking the attraction of the nucleus for the outer electrons, so the outer electrons feel a smaller effective nuclear charge. In atoms with more electrons, the inner shells repel and shield some of the positive pull of the nucleus, reducing the net attraction that outer electrons experience. This effective nuclear charge, often written as Z_eff = Z − S, helps explain why outer electrons are less tightly bound and how trends in the periodic table arise: shielding increases down a group (more inner shells), while across a period shielding stays relatively constant but Z increases, raising Z_eff and ionization energy. The described concept best matches the reduced attraction due to inner electrons. The other descriptions don’t fit: shielding is not an increase in nucleus–outer-electron attraction, it’s not about the energy released when an electron is removed, and it’s not about attraction between electrons outside the atom.