Question

the modern periodic table has been evolved to the early attempts of dobereiner, newlands , Mendeleev.and list one limitations of 3 attempts​

Answer 1

Explanation:

Dobereiner Periodic Table

Advantage: To predict the atomic mass of middle element in each triad

Limitation: Dobereiner could identify only three triads

Newland Periodic table

Advantage: Every eighth element had properties similar to that of first; co-related the properties of elements with their atomic mass.

Limitation: It was only applicable up to Calcium; only 56 elements and no future element

Mendeleev’s Periodic Table

Advantage: Elements with similar properties could be grouped. He predicted the existence of new elements that had not been discovered at that time.

Limitation: No fixed position for hydrogen/ position of isotopes. Atomic masses do not increase in a regular manner.