NCERT Solution for Class 10 Science Chapter 5
Periodic Classification of Elements
NCERT Books for Session 2020-2021
CBSE Board and UP Board
Intext Questions
Page No-81
Questions No-3
What were the limitations of Newlands’ Law of Octaves?
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Limitations of Newlands’ law of octaves:
a) It was not applicable throughout the arrangements. It was applicable up to calcium
only. The properties of the elements listed after calcium showed no resemblance
to the properties of the elements above them.
b) Those elements that were discovered after Newlands’ octaves did not follow the
law of octaves.
c) The position of cobalt and nickel in the group of the elements (F, Cl) of different
properties could not be explained.
d) Placing of iron far away from cobalt and nickel, which have similar properties as
iron, could also not be explained.
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1. Only applicable till Calcium.
2. We can fill only 56 elements in this table. These is no place to fit rest elements.
3. In order to fit elements into his Table, Newlands adjusted two elements in the same slot, but also put some unlike elements under the same slot.
4. 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.
5. Iron, which resembles cobalt and nickel in properties, has been placed far away from these elements.
6. With the discovery of noble gases, the Law of Octaves became irrelevant.
7. Newlands’ Law of Octaves worked well with lighter elements only.
1. It was found that the Law of Octaves was applicable only upto calcium, as after calcium every eighth element did not possess properties similar to that of the first.
2. Now we know more than 56 elements, but in Newland’s table only 56 elements can be placed,
1. Valid upto Ca only.
2. It was assumed by Newlands that only 56 elements existed in nature and no more elements would be discovered in the future. But, later on, several new elements were discovered, whose properties did not fit into the Law of Octaves.
S K Patil answer is easy and best describe the question.
All the answers are correct. But Patil is more explained.
Limitations of Newland’s Law of Octaves:
(i) Newland’s Law of Octaves was applicable up to calcium only.
(ii) Elements after Calcium did not obey the Newland’s Law of Octaves.
(iii) Newland adjusted two elements under the same slot inspite of their different properties, such as cobalt and chlorine were put in the same note while there properties were different.
(iv) It appears that Newland assumed that only 56 elements existed in nature; after discovery of more elements his Law could no longer hold true.