Consider four elements A, B, C, and D placed in a 2 2 grid in the p-block of the periodic table. Element A is in Group 15, Period 2; B is in Group 16, Period 2; C is in Group 15, Period 3; and D is in Group 16, Period 3. Evaluate the following statements regarding their properties: I. The order of first ionization enthalpy is D II. The order of atomic radius is B III. The order of negative electron gain enthalpy is C

Step-by-step solution

The elements are A (Nitrogen, N), B (Oxygen, O), C (Phosphorus, P), and D (Sulphur, S). Statement I: First ionization enthalpy generally increases across a period, but Group 15 elements have higher IE than Group 16 due to half-filled stable electronic configuration. Thus, N > O and P > S. Down the group, IE decreases, so N > P and O > S. The overall order is S Statement II: Atomic radius decreases across a period and increases down a group. Thus, O Statement III: Nitrogen has a positive electron gain enthalpy, maki