Rank the effective nuclear charge Z* experienced by a valence electron in each of these atoms:

Sure, I can help with that. To rank the effective nuclear charge $Z^*$ experienced by a valence electron in each of these atoms, follow these steps:

1. Identify the Atomic Number (Z): Determine the number of protons in the nucleus for each atom. This is the atomic number (Z).

2. Determine the Number of Core Electrons (S): Identify the number of electrons that are not in the valence shell. These are the core electrons.

3. Calculate the Effective Nuclear Charge (Z):* Use the formula $Z^* = Z - S$, where $Z$ is the atomic number and $S$ is the number of core electrons.

4. Compare the Effective Nuclear Charges: Rank the atoms based on the calculated $Z^*$ values.

Let's apply these steps to a set of example atoms: Sodium (Na), Magnesium (Mg), and Aluminum (Al).

1. Identify the Atomic Number (Z):

   • Sodium (Na): $Z = 11$
   • Magnesium (Mg): $Z = 12$
   • Aluminum (Al): $Z = 13$

2. Determine the Number of Core Electrons (S):

   • Sodium (Na): Core electrons = 10 (1s² 2s² 2p⁶)
   • Magnesium (Mg): Core electrons = 10 (1s² 2s² 2p⁶)
   • Aluminum (Al): Core electrons = 10 (1s² 2s² 2p⁶)

3. Calculate the Effective Nuclear Charge (Z):*

   • Sodium (Na): $Z^* = 11 - 10 = 1$
   • Magnesium (Mg): $Z^* = 12 - 10 = 2$
   • Aluminum (Al): $Z^* = 13 - 10 = 3$

4. Compare the Effective Nuclear Charges:

   • Sodium (Na): $Z^* = 1$
   • Magnesium (Mg): $Z^* = 2$
   • Aluminum (Al): $Z^* = 3$

Ranking:

• Aluminum (Al) > Magnesium (Mg) > Sodium (Na)

So, the effective nuclear charge $Z^*$ experienced by a valence electron is highest in Aluminum (Al), followed by Magnesium (Mg), and lowest in Sodium (Na).