Newlands’ octaves

Brief Information about Newlands' Octaves (System of classification of elements)

1. Newlands’ Octaves Group II

2. Contents Previous Attempts To Classify Elements & Why they failed? Some Information about Newlands Octaves and the Law of Octaves Advantages and Limitations of Octaves The correction of Newlands’ Octaves Some Extra Facts!

3. Previous Attempts to Classify Elements The method of arranging elements in groups of three(triads) was tried out by Johann Wolfgang Dobereiner . In this method, the elements in a triad were written in the order of increasing atomic masses; the atomic mass of the middle element was roughly the average of the atomic masses of the other 2 elements. This method failed because this did not work with elements that had very high or very low atomic numbers .

4. John Newlands The attempts of Dobereiner encouraged other chemists like relate the properties of elements with their atomic masses. One of these scientists/chemists was John Newlands. He was born on 26 November 1837 in Lambeth, Surrey, England. He was home schooled by his father, William Newlands. When he heard that Dobereiner was in the news for classifying elements based on their atomic masses and numbers, he was also determined to create a system that could classify elements. This system was known as the Law of Octaves created by him in 1866.

5. Octaves and the law of octaves This is the octaves table The law of octaves states that every eighth element had properties similar to the first element(hence, “ OCT”aves ). In this system, Newlands had placed every element known at that time i.e. from Hydrogen to Thorium (56 elements)

6. Advantages and Disadvantages of the Octave Classification Advantages:- It helped detect a periodic(Every 8 elements) pattern in the properties of elements This classification helped to develop better systems of classification Disadvantages:- This held true only for elements till Calcium. Newlands assumed that only 56 elements existed in nature. But, many more elements were discovered whose properties did not fit into the octaves. In order to fit elements into his table, Newlands adjusted two elements in the same slot and also adjusted some unlike elements under the same slot. The Law of Octaves worked well only with the lighter elements

7. Correction of Newlands’ Law of Octaves. The Law of Octaves was found to be very unreliable to classify and compare elements on the basis of chemical properties. Mendeleev(Dimitri) also tried to classify elements. This was known as Mendeleev’s periodic table, which was widely accepted as a system of classifications. Mendeleev’s periodic table was later corrected by Henry Moseley in 1913