Question

(i) Define the followings:
(a) Doberneir’s rule of triad (b) Periodicity (c) Modern periodic law (d) Electronegativity

Answer 1

Answer:

(b) periodicity= the correct Robin periodic is called periodicity and the tendency to recure at intervals.

Answer 2

Answer:

(a) According to Döbereiner law of triads, when elements are arranged in prder of increasing atomic masses so as to form triads of three different elements; then, the atomic mass of the middle element is roughly equal to the average of those of the extreme elements.

He discovered three triads, they are:

1. (Li, Na, K) 2. (Ca, Sr, Ba) 3. (Cl, Br, I)

(b) Periodicity is defined as the property of various elements to be subsequently repeated or recurred after a specific interval.

It was referred by the changing and repeating periods and groups.

(c) According to the Modern Periodic law, "The properties of the elements are the periodic functions of their atomic numbers"

This refers to that if we arrange the elements in the order of increasing atomic numbers, then their properties are a kind of repititions after a fixed interval.

(d) Electronegativity is defined as the property of any element to gain electron from its surrounding other elements to become electronegatively stable.