Question

Q4. Classify the following elements according to the Law of Octaves:

K, Na, Ca, S, O, P, Al

N, F, Si, C, Cl, Mg​

Answer 1

Answer:

They’ll be arranged in order as follows:

H Li Be B C N O

F Na Mg Al Si P S

Cl K Ca

Explanation:

According to law of octaves every 8th element repeats the property of the first.

They are arranged in order of increasing atomic weight.

At the time when this was proposed Noble gases were unknown.

The rule was applicable till Calcium (atomic weight 40) only, this means till lighter elements only .

After the discovery of Noble gases it became useless completely as now every ninth element repeats the properties.