What are the differences between Mendeleev and modern periodic table?

Answer 1

Mendeleev invented the periodic table in 1869.

In those days there were still elements missing, they had no idea of what electrons were or how they related to chemistry, or how the nucleus related to atomic weight.;

but they're really the same charts.

Answer 2

Mendeleev's Periodic Table was arranged based on increasing Atomic Mass, with gaps left for undiscovered elements. The modern periodic table is arranged based on increasing atomic number, with elements grouped by properties and electron configurations. Additionally, the modern periodic table incorporates the concept of periods and groups, which was not present in Mendeleev's original table.

Answer 3

The modern periodic table was based on mendeleev's table however the modern one has the gaps filled (gallium, germanium and francium) that mendeleev left out as they had not yet been discovered.

the other change was to ignore the atomic weights rule and switch adjacent elements such as cobalt and nickel to better classify them into groups ( columns where valency is the same).

Hope that helps :)

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Answer 4

In Mendeleev's periodic table the elements were organised with increasing atomic weight whereas in the modern periodic table they are arranged with increasing atomic number.