Chemistry - PERIODIC TABLE Question with Solution | TestHub

(A) $Z_{eff}$ of the last electron of Na & K are equal.

For alkali metals, the outermost electron experiences nearly the same effective nuclear charge:

$$Z_{eff}\approx 1$$

(B) Lattice energy of NaF > NaCl.

F⁻ is smaller than Cl⁻, so the interionic distance is less and the attraction is more:

$$NaF>NaCl$$

(C) Li is the strongest reducing element.

In aqueous solution, Li⁺ has very high hydration energy, making Li the strongest reducing agent among alkali metals.

(D) All Xe–F bond lengths are equal in XeF₅⁻.

XeF₅⁻ has a symmetrical pentagonal planar structure, so all Xe–F bonds are equivalent.

Correct Option: A, B, C, D