Choose the statement that is TRUE.
A) Outer electrons efficiently shield one another from nuclear charge.
B) Core electrons effectively shield outer electrons from nuclear charge.
C) Valence electrons are most difficult of all electrons to remove.
D) Core electrons are the easiest of all electrons to remove.
E) All of the above are true.

Question

Quizplus · Accepted Answer

Core electrons, being closer to the nucleus, are more effective at shielding outer electrons from nuclear charge. This is the basis for the concept of effective nuclear charge. Outer electrons, on the other hand, are more easily removed and are known as valence electrons. Option A is false since outer electrons do not efficiently shield one another from nuclear charge, hence the increase in ionization energy going from left to right across a period. Option C is also false since valence electrons are the easiest of all electrons to remove due to their location in the outermost energy level. Option D is false since core electrons are the most tightly bound electrons and require a higher amount of energy to be removed.

Choose the Statement That Is TRUE