Question

The Ce (Z = 58) belongs to IIIrd group of periodic table. If it
furnish one α particle to form an element 'X', then X belongs
to
(a) IIIʳᵈ group (b) IIⁿᵈ group
(c) Iˢᵗ group (d) zero group

Answer 1

If Ce (Z = 58) furnish one α particle to form an element 'X', then X belongs

to IIⁿᵈ group

- when an element loses an α particle, its atomic no (Z) is decreased by 2 and its mass no decreases by 4

- so when Cerium loses an alpha particle,then the atomic no of resultant element X = 58 - 2

                 = 56

- this element X with Z = 56 is Barium and it belongs to the IInd group of the periodic table

-so the correct answer is option (b)