Question

Why are the noble gases missing from Newlands' octaves?
(class 10 CBSE SAMPLE PAPER 2017-18 SCIENCE)

Answer 1

Solution:
John Newlands in 1864 gave the law of octaves.

Newlands’ law of octaves state that when elements are arranged in the order of increasing atomic masses the physical and chemical properties of every 8th element are a repetition of the first element.

The noble gases are missing from Newlands' octaves because these elements for not known at that time. If the noble gases are included in Newlands’ octaves, Newlands’ arrangement of elements will not fit the musical scale with the eighth note resemble the first one.

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Answer 2

during the period when newland discovered his periodic table at that time noble gases were not been founded and according his thinking at that time there only those elements in earth crust which he has been discovered and these gases were tried to arrange in newland periodic table it disturbed arrangement of atoms in his periodic table