posted by Maddie .
What were the undiscovered elements of Mendeleev's periodic table?
He called the predicted element ekasilicon,we now know it as Ge.
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Weren't there more then one?
eka-boron now Al
eka Si now Ge
eka Al now Ga
I understand there were two others but I've been unable to find them. I think one MAY have been Tc, element #43.
OK. I found it.
There were four that have been fairly widely spoken of; i.e.,
eka B -- Sc
eka Si -- Ge
eka Mn -- Tc
After the discovery of He and Ar, Mendeleev placed those in his chart and predicted that there should be another group 0 element lighter than He and thought that it might be responible for radioactivity. Of course that never materialized since hydrogen is the lightest element known. In addition, he suggested an element heavier than He and Ar, which he named coronium (from the sun) since he observed a spectral line in the sun that had not been identified with any other element. That was later proved to be false, also. The calibration of the spectral instrument he used was not done correctly, the line was later remeasured and the new wavelength showed it to be iron, an element already known at the time. Good thing those later predictions weren't his first; otherwise, much of the popularity of his new table rested on the prediction of the new elements and their properties he would have been ridiculed instead of praised.