Question

13. Arrange the following:
(a) Elements of group 1, in increasing order of reactivity.
(b) Elements of group 17, in decreasing order of reactivity.
(c) He, Na, Mg (increasing order of melting point).​

Answer 1

Answer:

(a) The increasing order of reactivity among group 1 elements is Li < Na < K < Rb is F > CI > Br > I. Explain. In group 1 elements (alkali metals) the reactivity of the metals is mainly due to the electron releasing tendency of their atoms, which is related to ionisation enthalpy.

(b) Elements of group 17, in decreasing order of reactivity are F > Cl > Br > I. Explanation: Elements of group 17 are fluorine, chlorine, bromine and iodine. Being non-metals, these elements has the ability to gain electron in order to gain stability.

(c) Increasing order of melting point are He < Na < Mg