the quality or character of being periodic; the tendency to recur at intervals. is knw as periodicity. :)
the phenomenon of repeatation of properties of elements after a regular interval in terms of valency chemical properties, physical properties


A property that regularly keeps changing inm groups anfd periods
I thnk.. k It is the recurrence of Similar properties after Regular intervals..
In studying the characteristics of various elements, the early chemists started to list various properties. John Dalton devised a means to determine a relative mass for the atoms of the elements.  Mendeleev arranged the 60 elements he knew of at the time in order of each element's increasing mass. This showed him a repeating pattern of other characteristics of the elements. The tendency to show a regular repeating pattern is known as periodicity.

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