Final answer:
The shielding constant for the last valence electron of aluminum is calculated based on its electron configuration. With two 3s electrons contributing to the shielding, the correct answer for the shielding constant is d) 2.
Step-by-step explanation:
The calculation of the shielding constant (S) for the last valence electron of aluminum involves understanding the electron configuration of aluminum and how inner electrons shield outer electrons from the full charge of the nucleus. The electron configuration for aluminum is 3s²3p¹. For aluminum, the valence electron configuration shows two 3s² electrons that contribute significantly to the shielding of the 3p electron.
Using the provided information and considering the number of electrons between the nucleus and the valence electron in question, we can calculate the effective nuclear charge (Zeff) using the formula Zeff = Z - S, where Z is the atomic number and S is the shielding constant. For aluminum (Z=13), the 3s² electrons would contribute a shielding constant of approximately 2, leading to an answer of d) 2 for the shielding constant of the last valence electron of aluminum.