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Ch.7 - Periodic Properties of the Elements
Chapter 7, Problem 81b

(b) Repeat these calculations using Slater’s rules.

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1
Identify the electron configuration of the element in question. Determine the number of electrons in each shell and subshell.
Apply Slater's rules to calculate the shielding constant (\( \sigma \)) for each electron. Remember that electrons in the same group, inner shells, and different shells contribute differently to the shielding.
Calculate the effective nuclear charge (\( Z_{\text{eff}} \)) using the formula: \( Z_{\text{eff}} = Z - \sigma \), where \( Z \) is the atomic number and \( \sigma \) is the total shielding constant.
Consider the contributions of different electron groups: Electrons in the same shell, electrons in the \( n-1 \) shell, and electrons in shells \( n-2 \) or lower, each with their respective shielding values.
Sum up the contributions from all electrons to find the total shielding constant, and use it to determine the effective nuclear charge.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Slater's Rules

Slater's Rules are a set of guidelines used to estimate the shielding effect of electrons in multi-electron atoms. They provide a systematic way to calculate the effective nuclear charge (Z_eff) experienced by an electron, taking into account the contributions of other electrons. By applying these rules, one can determine how much an electron is shielded from the full positive charge of the nucleus, which is crucial for understanding atomic structure and electron configurations.
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Effective Nuclear Charge (Z_eff)

Effective Nuclear Charge (Z_eff) is the net positive charge experienced by an electron in a multi-electron atom. It is calculated by subtracting the shielding effect of other electrons from the actual nuclear charge. Z_eff influences various atomic properties, including ionization energy and atomic size, as it determines how strongly an electron is held by the nucleus. Understanding Z_eff is essential for predicting the behavior of atoms in chemical reactions.
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Shielding Effect

The shielding effect refers to the phenomenon where inner-shell electrons partially block the attractive force of the nucleus on outer-shell electrons. This results in outer electrons experiencing a reduced effective nuclear charge. The extent of shielding varies depending on the electron configuration and the arrangement of electrons in an atom. Recognizing the shielding effect is vital for accurately calculating Z_eff and understanding trends in the periodic table.
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