Question

storyline 1 exam
41 of 73
which of the following statements about the shielding effect and effective nuclear charge are true? select all that apply.
the actual attraction felt by the electrons farthest from the nucleus is less than the numerical value based on coulombs law
valence electrons always shield one another.
the effective nuclear charge zeff is defined as the net positive nuclear charge that an atoms electron experiences
inner core electrons always shield valence electrons
the shielding effect describes how the repulsive forces between electrons work to reduce the amount of attractive force between electrons
the shielding effect describes how the attractive forces between electrons work to increase the amount of attraction each electron feels.

Explanation:

• First statement: Due to shielding effect (electron - electron repulsion), the actual attraction on outer electrons is less than Coulomb's law prediction (which assumes no electron - electron repulsion).
• Second statement: Valence electrons do not always shield one another. For example, in some cases (like in a linear molecule with a particular electron - electron orientation), the shielding is not significant.
• Third statement: By definition, effective nuclear charge \(Z_{eff}\) is the net positive charge an electron experiences (accounting for shielding).
• Fourth statement: Inner core electrons are closer to the nucleus and always shield valence electrons (as they are between the nucleus and valence electrons).
• Fifth statement: Shielding effect is about electron - electron repulsion (which is a repulsive force) reducing the attraction between nucleus and outer electrons.
• Sixth statement: Shielding effect is due to repulsion, not attraction between electrons.

Answer:

• The actual attraction felt by the electrons farthest from the nucleus is less than the numerical value based on Coulomb's law.
• The effective nuclear charge \(Z_{eff}\) is defined as the net positive nuclear charge that an atom's electron experiences.
• Inner core electrons always shield valence electrons.
• The shielding effect describes how the repulsive forces between electrons work to reduce the amount of attractive force between electrons.