. Explain the Newland’s Octet Law
Newland’s Octet Law, 1864: Very shortly after the discovery of telluric helix. John Alexander Reina Newland in England made the first attempt to correlate the chemical properties of the elements with their atomic weights. If the elements are arranged in order of their increasing atomic weights, every eighth element had similar properties to first one like the first and eighth note in music. For example,
The system worked quite well for the lighter elements. For example, H, F and Cl show similar properties and Li, Na and K exhibit same characteristics. The system, however, fails in the case of heavier elements as manganese has been placed along with nitrogen and phosphorus or iron has been placed along with oxygen and sulphur i.e. dissimilar elements have been grouped which is against the aim of classification. Also note that no space was left for the elements which were unknown at that time and many elements were provided wrong positions on account of wrong values of atomic masses in this classification.