Question

What were the limitations of Newlands classification?
a) it was applicable only for lighter elements
b) He adjusted two elements in the same place
c)The pattern was only observed up to calcium
d) All of the above

Answer 1

Hint: In order to understand and answer the given question, the prerequisite is to know what is the basis of Newlands classification and what were the reasons that led to the formation of a new classification, i.e. what caused the failure of the Newlands classification. A small knowledge about atomic numbers and periodicity will help in answering the question.

Complete answer:
The classification given by John Newlands of the elements and the basis of arrangement of the elements was on the increasing order of the atomic masses.
When the elements were arranged in the increasing order of their atomic masses, it was noted that the properties were getting repeated after every eighth element. On this observation, the Newlands octave’s rule got formulated. However, there were certain drawbacks that made the classification of Newlands less perfect. Those limitations included:
i) In a single slot, there were more than two elements added. For example, cobalt and nickel were in the same slot.
ii) Elements with atomic masses greater than that of calcium were noticed to not follow the octave’s rule and were deviating. Hence, Newland’s classification was only up to calcium elements.
Thus, from the above two limitations discussed above, we can deduce that of the given options in the question, we can see that the correct one is an option (d); i.e. all of the above.

Note:
There were certain other limitations too which were present in the Newlands octave’s rule and its classification, including certain dissimilar elements to, were placed in the same slot, which was wrong. Other than that, when the noble gas was discovered, then the definition changed to every ninth element following the first element.