In Which year did John Newlands propound the 'Law of Octaves' an innovative concept proposing the periodicity of chemical elements arranged in the order of atomic weight?

The correct answer is 1865.

Key Points

• The 'Law of Octaves' was propounded by the English chemist J.A.R. Newlands in 1865.
• The 'Law of Octaves'states that if the chemical elements are arranged according to increasing atomic weight, those with similar physical and chemical properties occur after each interval of seven elements.
• J.A.R. Newlands was the first to disclose a periodic pattern in the properties of the elements and anticipated later developments of the periodic law.​

Additional Information

There were the following limitations of the Newland's Law of Octaves

• It was found that the Law of Octaves was applicable only up to calcium, as after calcium every eighth element did not possess properties similar to that of the first.
• It was assumed by Newlands that only 56 elements existed in nature and no more elements would be discovered in the future. But, later on, several new elements were discovered, whose properties did not fit into the Law of Octaves.
• After the discovery of the Noble gases, the Law of Octaves became irrelevant. Thus, Newlands’ Law of Octaves worked well with lighter elements only.