Elements have been arranged in the following sequence on the basis of their increasing atomic masses. F, Na, Mg, Al, Si, P, S, Cl,Ar, K.
(a) Pick two sets of elements which have similar properties
(b) The given sequence represents which law of classification of elements ?

Explanation

(a) Here, the elements are arranged in the order of increasing atomic masses, so according to Newlands' law of octaves there is a repetition of every eighth element as compared to the given element. The two sets of elements which have similar properties are
F and Cl are first and eighth element in the above sequence, therefore, they have similar properties. Although Na and K have similar properties but they are not related as first and eighth element in the above sequence
(b) The given sequence is according to Newlands's law octaves represented as
`"F Na Mg Al Si P S Cl Ar K"`