NEETChemistryClassification of Elements and Periodicity in Properties
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. In the light of the above statements, choose the most appropriate answer from the options given below
Options
- AStatement I is incorrect but statement II is correct.
- BBoth the statements I and II are correct
- CStatement I is correct but statement II is incorrect
- DBoth the statements I and II are incorrect
Correct answer
B. Both the statements I and II are correct
Step-by-step solution
First ionization enthalpy (IE 1 ) of B, Al, Ga are 801, 577 and 579 kJ/mol respectively. As decrease in first ionization enthalpy is much larger from B to Al. ∆ IE 1 of B and Al is greater than ∆ IE 1 of Al and Ga. So, the statement I is correct. This is due to completely filled d-orbitals in Ga and d-electron have low screening effect to compensate the increase in nuclear charge. So, The statement II is also correct. Hence, the correct option is B.