Effective Nuclear Charge Concepts

The video tutorial explains the periodic trend of effective nuclear charge (Z effective) in the periodic table. It describes how Z effective increases as you move from left to right across a period due to an increase in nuclear charge with minimal change in the screening constant. Conversely, as you move down a group, Z effective remains approximately constant because the increase in nuclear charge is offset by an increase in the screening constant due to more core electrons. The tutorial uses examples of elements like lithium, oxygen, and sodium to illustrate these concepts.

What is the primary factor that causes the effective nuclear charge to increase across a period?

• Decrease in atomic radius

• Decrease in the number of core electrons

• Increase in the number of protons

• Increase in the number of valence electrons

Why does the shielding constant 's' remain relatively constant across a period?

• The number of core electrons remains the same

• The number of valence electrons decreases

• The number of protons decreases

• The atomic radius increases

Which element has a higher effective nuclear charge, lithium or oxygen, and why?

• Oxygen, because it has fewer core electrons

• Lithium, because it has more core electrons

• Oxygen, because it has more protons

• Lithium, because it has fewer protons

What is the relationship between nuclear charge (Z) and effective nuclear charge (Z effective)?

• They are inversely proportional

• They are directly proportional

• They are equal

• They are unrelated

What happens to the effective nuclear charge as you move down a group?

• It remains approximately constant

• It decreases significantly

• It fluctuates randomly

• It increases significantly

How does the number of core electrons change as you move down a group?

• It fluctuates

• It increases

• It remains the same

• It decreases

What is the effect of increased core electron shielding as you move down a group?

• It enhances the nuclear charge felt by valence electrons

• It reduces the nuclear charge felt by valence electrons

• It has no effect on the nuclear charge

• It increases the atomic radius

In the context of effective nuclear charge, what does the term 'screening' refer to?

• The decrease in atomic mass

• The blocking of nuclear charge by core electrons

• The process of increasing atomic radius

• The increase in valence electrons

Why does the effective nuclear charge not change much as you move down a group?

• Because the increase in nuclear charge is offset by increased shielding

• Because the number of protons decreases

• Because the number of valence electrons increases

• Because the atomic radius decreases

What is the main reason for the effective nuclear charge remaining constant down a group?

• The decrease in nuclear charge

• The increase in valence electrons

• The decrease in atomic radius

• The increase in core electrons balances the increase in nuclear charge