Question

why did mendeleev have gap in his periodic table

Answer 1

The elements were arranged according to the atic mass...there were irregularities between 2 elements...that's why his periodic table had gap..

Answer 2

he had kept gaps in his periodic table as he predicted future elements as well and kept the place.

Also he predicted the properties of elements as well.

for example: he predicted ekka aluminum and today it is called gallium.

hope this will help you :-)
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