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

Solution

Chemistry ma’am · 4 steps

Reactivity is highest at both ends of a period, not steadily rising, and group 18 barely reacts at all.

1. Statement I. Group 1 metals react fast because they lose one electron easily. Group 17 non-metals react fast because they gain one electron easily. Elements in the middle are less reactive, and the group 18 noble gases are almost unreactive.
2. Reactivity pattern. Across a period, reactivity is high at the left, falls towards the middle, rises again up to group 17, then drops sharply at group 18. It does not increase steadily from group 1 to 18, so Statement I is false.
3. Statement II. Metallic character falls across a period, so the oxides change from basic to acidic. In period 3, Na₂O is strongly basic and gives NaOH in water, while Cl₂O₇ is strongly acidic and gives HClO₄. So Statement II is true.
4. So. Statement I is false and Statement II is true, which is option (a).

The idea to keep. Along a period, reactivity is a U-shape: highest at groups 1 and 17, lowest in the middle, with group 18 inert. Oxides go from basic on the left to acidic on the right.

Answer from the NTA final answer key. Solution by PrepWiser.