Question

The Increasing order of reactivity among group 1 elements is Li < Na < K < Rb < Cs Where as that of group 17 is F > Cl > Br > L . Explain !!​

Answer 1

Answer:

In Group 1, the elements have 1 valence electron in their valence shell. Hence while reacting they tend to lose this electron and become a cation. Now the reactivity of elements in group 1 to form a cation depends on the Effective Nuclear Charge.

As we go down a group, the atomic radii increases due to which force of attraction between the valence electrons and the nucleus decreases. Therefore the element in the bottom of the group will lose electron easily as it has less force of attraction by the nucleus.

But in case of Group 17, they need 1 electron to become stable. Thus 1 electron liberated by an atom is attracted more easily if the nuclear attraction is more. Thus Fluorine having only 1 shell has more nuclear attraction due to which it forms the product readily.

Hence the order of reactivity in Group 1 is Li < Na < K < Rb < Cs while that of Group 17 is F > Cl > Br > I.

Hope it helped !!

Answer 2

Explanation:

28 The increasing order of reactivity among group 1 elements is Li < Na < K < Rb < Cs whereas that of group 17 is F > Cl > Br > I. Explain. Ans. The elements of group 1 have only one electron in their respective valence shells and thus, have a strong tendency to lose this electron.