Question

State Newlands law of Octaves.

Answer 1

Hint: We know that the Newlands law of Octaves was given by John Newlands. Newland first detected a periodic pattern in the periodic properties of the elements and later developed periodic law. It provides the information about the similarities between elements in the periodic table.

Complete answer:
Newland stated that if the elements are arranged in the order of their relative atomic masses with some transpositions, the number of similar elements differs by multiples of seven.
For example we can consider the nitrogen group. In the nitrogen group, phosphorus is the seventh element after nitrogen, arsenic is the seventh element after phosphorus, antimony is the seventh element after arsenic.
Newland stated that with every seventh element, the eight element is similar to the first of the previous seventh element.
The Newlands law of Octaves was not accepted as it had many limitations. The limitations of Newlands law of Octaves are as follows:
-Newlands law of Octaves does not hold well for the elements which lie beyond calcium. After calcium every eighth element does not possess the properties similar to the first element.
-The elements that are discovered later do not obey Newlands law of Octaves.
We know that the properties of iron are similar to that of cobalt and nickel. But iron is placed far away from cobalt and nickel. Thus, we can conclude that the Newlands law of Octaves is obeyed only by the lighter elements.

Note: Do not get confused because of the word ‘octaves’. The similarity in the properties is observed after seven elements and not after eight elements. Some people confuse it with that It focuses on the stability of the elements that should be the number of electrons in a particular energy level, but that's not the case.