Newlands' Law of Octaves - Class XI

Newland's Law of octaves stated that if elements (known at Newland's time) were arranged in increasing order of their atomic weights, every eighth element had properties similar to the first element. For example, Li and Na have similar properties.

The limitations of Newlands' classification were:

• It was only applicable for lighter elements.
  
• He adjusted two elements in one place.
  
• The pattern was only observed up to calcium.
  

Newlands' law of octaves worked well with lighter elements only. As the weight is increased, the pattern started changing and was no longer following the law.

The placement of elements in the Newlands' periodic table was compared to the notes of music where the first note and the eighth note are same. Similarly, in Newlands' periodic table, the chemical properties also repeat after $7$ elements.

In Newlands' table, chlorine, bromine and fluorine were placed in the same group in which cobalt and nickel were present.

In Newland's periodic table, $1$st element and the $8$th element have the same chemical property, i.e., they belong to the same group. So, the table will look like:
$\begin{equation}X;1;2;3;4;5;6 \ Y\end{equation}$
So, there are $6$ elements between X and Y.

In 1864 newlands in chemistry, the generalization made by the English chemist J.A.R. Newlands in 1865 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. Newlands was one of the first to detect a periodic pattern in the properties of the elements and anticipated later developments of the periodic law. Hence called law of octaves.

He observed that every eighth element had properties similar to the first element. Elements after atomic no. 40 do not fit in this rule.

The discovery of zero group of elements (inert gases) gave a death blow to the Newland's Law.
According to Newlands Law of octaves, when the elements are arranged in the increasing order of atomic weights, the properties of every eighth element are similar to the first one.

The octet rule in chemistry refers to the tendency of atoms to prefer to have eight electrons in the valence shell. Beryllium (Be) and Boron (B) are electron-deficient elements that often form compounds with fewer than eight valence electrons, thus failing to follow the octet rule.

Newlands' law of octaves states that every eighth element has properties similar to the first. If X is the first element, the eighth element is Y. The number of elements between them is 8 - 1 - 1 = 6.

The Newland's law of octaves for the classification of elements was found to be applicable only up to the element calcium.

According to the law of octaves, those with similar physical and chemical properties occur after each interval of seven. 

Iron resembled cobalt and nickel and in Newlands' table was placed far away from those elements. It was placed in the last group in Newlands' table.

In Newlands' periodic table, cobalt and nickel were placed together in the same slot because they had similar properties, despite their atomic weight differences.

John Newlands arranged the known elements in an increasing order of their atomic masses. He started with the element having the lowest atomic mass ( hydrogen ) and ended at thorium which was the $56^{th}$ element. Some of the elements satisfying this order are arranged as $H, Li, Be, B, C, N, O$.

Elements have been arranged in the following sequence on the basis of their increasing atomic masses.

According to Newland Octave law, when elements are arranged in increasing atomic mass every eighth element has similar properties to the first element.