Detailed calculations show that the value of Zeff for the outermost electrons in Si and Cl atoms is 4.29+ and 6.12+, respectively. (a) What value do you estimate for Zeff experienced by the outermost electron in both Si and Cl by assuming core electrons contribute 1.00 and valence electrons contribute 0.00 to the screening constant?

Verified step by step guidance

1. insert step 1: Identify the atomic numbers of silicon (Si) and chlorine (Cl). Silicon has an atomic number of 14, and chlorine has an atomic number of 17.
2. insert step 2: Determine the number of core and valence electrons for each element. For Si, there are 10 core electrons and 4 valence electrons. For Cl, there are 10 core electrons and 7 valence electrons.
3. insert step 3: Calculate the screening constant (S) for each element. Since core electrons contribute 1.00 and valence electrons contribute 0.00, the screening constant for Si is 10, and for Cl, it is also 10.
4. insert step 4: Use the formula for effective nuclear charge (Z_{eff}): Z_{eff} = Z - S, where Z is the atomic number and S is the screening constant.
5. insert step 5: Substitute the values into the formula for each element. For Si, Z_{eff} = 14 - 10. For Cl, Z_{eff} = 17 - 10.

Key Concepts

Effective Nuclear Charge (Zeff)

Effective Nuclear Charge (Zeff) is the net positive charge experienced by an electron in a multi-electron atom. It accounts for the actual nuclear charge (the number of protons) and the shielding effect caused by other electrons. The greater the Zeff, the stronger the attraction between the nucleus and the outermost electrons, influencing their energy levels and chemical behavior.

Shielding Effect

The shielding effect refers to the phenomenon where inner electrons partially block the attractive force of the nucleus on outer electrons. This results in a lower effective nuclear charge felt by the outer electrons. In calculations, core electrons typically contribute a fixed value to the screening constant, while valence electrons contribute less, reflecting their proximity to the nucleus.

Valence and Core Electrons

Electrons in an atom are categorized as valence or core electrons. Valence electrons are those in the outermost shell and are involved in chemical bonding, while core electrons are located in inner shells and do not participate in bonding. Understanding the distinction between these two types of electrons is crucial for calculating Zeff, as they contribute differently to the shielding effect.