The incorrect statement is
- (A)The first ionization enthalpy of K is less than that of Na and Li
- (B)Xe does not have the lowest first ionization enthalpy in its group
- (C)The first ionization enthalpy of element with atomic number 37 is lower than that of the element with atomic number 38 .
- (D)The first ionization enthalpy of Ga is higher than that of the d-block element with atomic number 30.✓ Correct
Answer: (D)
Solution
Let's evaluate each statement:
(A) Correct: Ionization enthalpy decreases down a group, so K < Na < Li.
(B) Correct: In Group 18, the order is He > Ne > Ar > Kr > Xe > Rn. Xe does not have the lowest (Rn does).
(C) Correct: Element 37 is Rb (alkali metal), element 38 is Sr (alkaline earth). Alkali metals have lower ionization enthalpy than alkaline earth metals in the same period.
(D) Incorrect: Element 30 is Zn (d-block), Ga is element 31 (p-block). Zn has a stable configuration, giving it higher ionization enthalpy than Ga. So Ga < Zn, not Ga > Zn.
The answer is (D).
(A) Correct: Ionization enthalpy decreases down a group, so K < Na < Li.
(B) Correct: In Group 18, the order is He > Ne > Ar > Kr > Xe > Rn. Xe does not have the lowest (Rn does).
(C) Correct: Element 37 is Rb (alkali metal), element 38 is Sr (alkaline earth). Alkali metals have lower ionization enthalpy than alkaline earth metals in the same period.
(D) Incorrect: Element 30 is Zn (d-block), Ga is element 31 (p-block). Zn has a stable configuration, giving it higher ionization enthalpy than Ga. So Ga < Zn, not Ga > Zn.
The answer is (D).
JEE Main · 2022 · 27 Jul 2022 · Shift 1 · Single correct option