Question

Statement I: Along the period, the chemical reactivity of the element gradually increases from group 1 to group 18.
Statement II: The nature of oxides formed by group 1 element is basic while that of group 17 elements is acidic.
In the light of the above statements, choose the most appropriate from the questions given below:

• A. Both statement-I and statement-II are true
• B. Statement-I is true and statement-II is false
• C. Statement-I is false and statement-II is true
• D. Statement-I and statement-II both are false

Answer 1

Answer: (C)

Statement-I is false and statement-II is true

Answer 2

Statement I is incorrect. Chemical reactivity does not increase along the period. Instead:

For metals (on the left side of the periodic table), chemical reactivity decreases as we move across the period because ionization energy increases.

For nonmetals (on the right side of the periodic table), chemical reactivity increases as we move across the period due to higher electronegativity and electron affinity.

Thus, the chemical reactivity shows no uniform trend across the period, and the statement is false.

Statement II is correct. The oxides formed by:

• Group 1 elements (alkali metals) are basic in nature because these elements form oxides like Na2O and K2O, which react with water to form strong bases (e.g., NaOH).
• Group 17 elements (halogens) are acidic in nature because their oxides, like Cl2O7, react with water to form strong acids (e.g., HClO4).

Thus, Statement II is true.

Thus, the evaluation of the statements leads to the conclusion that: Statement I is false while Statement II is true, making the correct answer: