Doberniner's traids and Newland law of octave & Limitation||Class11th Chemistry|| Chapter 3 | Part 1

Here are clear, exam-ready descriptions for Dobereiner's Triads and Newlands' Law of Octaves, tailored perfectly for Class 11 Chemistry (Classification of Elements and Periodicity in Properties). #periodicity#dobereinerTraid#Newlandlaw#classificationofelements ​1. Dobereiner's Triads (1817) ​German chemist Johann Wolfgang Dobereiner was the first to illustrate a relationship between the chemical properties of elements and their atomic weights. He arranged elements with similar properties into groups of three, known as triads. ​The Law: When elements are arranged in the order of increasing atomic masses, the atomic mass of the middle element is roughly the arithmetic mean (average) of the atomic masses of the other two elements. ​Example: The Alkali Metal Triad Limitations ​It was not universally applicable. Dobereiner could identify only a few triads from the elements known at that time.. 2. Newlands' Law of Octaves (1865) ​English chemist John Alexander Newlands proposed a deeper relationship after arranging elements in increasing order of their atomic weights. He noticed a rhythmic pattern similar to musical notes. ​The Law: When elements are arranged in increasing order of their atomic weights, the properties of every eighth element are a repetition of the properties of the first element, similar to the eighth note in an octave of music (sa, re, ga, ma, pa, dha, ni, sa). Periodicity - It is the Repeation of physical and chemical properties or Gradual decrease or increase in physical and chemical properties after a fixed time intervals called Periodicity...