ICSE Class 9 Answered

Yes, Dobereiners triads also exist in the columns of Newlands Octaves.

 Consider the elements lithium (Li), sodium (Na) and potassium (K) which are present in the second column of Newlands classification of elements. Now, if we start with lithium as the 1^st  element, then the 8^th element from it is sodium and according to Newlands law of octaves, the properties of the 8^th element, sodium should be similar to that of the 1^st element, lithium. Again, if we take sodium as the 1^st element, then the 8^th element from it is potassium and according to Newlands law of octaves, the properties of the 8^th element, potassium should be similar to that of the 1^st element, sodium. This means that according to Newlands law of octaves, the elements lithium, sodium and potassium should have similar chemical properties. We also know that lithium, sodium and potassium form a Dobereiner's triad having similar chemical properties. From this, we conclude that Dobereiners triads also exist in the columns of Newlands Octaves.

Li	Ca	Cl
Na	Sr	Br
K	Ba	I