Question

Which of the following causes a decrease in the effective nuclear charge felt by the valence electrons? Select the correct answer below O removal of an electron from the valence shell to form a cation. O addition of an electron to the valence shell to form an anion O both of the above 0 none of the above

Answer 1

The effective nuclear charge felt by valence electrons decreases both when an electron is removed to form a cation, due to less electron-electron repulsion and a stronger nuclear pull, and when an electron is added to form an anion, due to increased electron repulsion.

Step-by-step explanation:

The effective nuclear charge felt by valence electrons decreases for two main reasons:

• When an electron is removed to form a cation, fewer electrons are present that results in decreased electron-electron repulsions and an increased pull by the nucleus on the remaining electrons.
• For an anion, adding an electron increases repulsions among electrons, effectively reducing the nuclear charge felt by each electron because they are slightly further apart and more shielded.

Therefore, the correct answer to which of the following causes a decrease in the effective nuclear charge felt by the valence electrons is both the removal of an electron to form a cation and the addition of an electron to form an anion.