What were the limitations of Newlands’ Law of Octaves?

Explanation

(i) The Law of Octaves was applicable only up to calcium (i.e., lighter elements) as after calcium, every eighth element did not possess properties similar to that of the first.
(ii) Newlands assumed that only 56 elements existed in nature and no more elements would be discovered in the future. After sometime, several new elements were discovered whose properties did not fit into the Law of Octaves.
(iii) Newlands adjusted two elements in the same slot, but also put some unlike elements under the same slot. For example, cobalt and nickel are in the same slot and these are placed in the same column as fluorine, chlorine and bromine which have very different properties than these elements. Iron, which resembles cobalt and nickel in properties, has been placed far away from these elements.