Question

What did Mandeleeff discovered and in which year?

if you know then only answer it. ​

Answer 1

Answer:

In 1869, just five years after John Newlands put forward his Law of Octaves, a Russian chemist called Dmitri Mendeleev published a periodic table.Mendeleev also arranged the elements known at the time in order of relative atomic mass, but he did some other things that made his table much more successful.

Explanation:

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Answer 2

Explanation:

he prepared periodic table.in the year 1869..

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