Given below are two statements:

Statement I: The decrease in first ionization enthalpy from B to Al is much larger than that from Al to Ga.

Statement II: The d orbitals in Ga are completely filled.

Question

Given below are two statements:

Statement I: The decrease in first ionization enthalpy from B to Al is much larger than that from Al to Ga.

Statement II: The d orbitals in Ga are completely filled.

Canvas Classes · Accepted Answer

Strategy:
 Contrast the shielding efficiency of , , and  orbitals. Poor shielding by inner -orbitals increases the effective nuclear charge on valence electrons, leading to smaller-than-expected size and higher ionization enthalpy.

Step 1: Evaluate Statement I
- Atomic numbers: B (), Al (), Ga ().
-  values (): .
-  drop: .
-  variation:  (increase).
The decrease from B to Al is indeed significantly larger than the virtually non-existent drop from Al to Ga. (True)

Step 2: Evaluate Statement II

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