Assertion : Group 18 elements have high ionization energies.
Reason: Group 18 elements have a complete outermost shell of electrons.
Both assertion and reason are true, and the reason is the correct explanation of the assertion.
Both assertion and reason are true, but the reason is not the correct explanation of the assertion.
The assertion is true, but the reason is false.
The assertion is false, but the reason is true.
The correct answer is (A) Both assertion and reason are true and reason is the correct explanation of the assertion. Group 18 elements have high ionization energies because they have a complete outermost shell of electrons, which are strongly attracted to the nucleus and require a large amount of energy to remove. This also contributes to their stability and inertness. Hence option A is the correct answer.
Option (B) is incorrect because it incorrectly states that the assertion is correct but the reason is incorrect. Both the assertion and reason are correct. Hence option B is incorrect.
Option (C) is incorrect because it incorrectly states that the assertion is incorrect but the reason is correct. The assertion is correct, and the reason is also correct. Hence option C is incorrect.
Option (D) is incorrect because it incorrectly states that both the assertion and reason are incorrect. Both the assertion and reason are correct. Hence option D is incorrect.