Write two points of differences between Mendeleev’s Periodic Table and the Modern Periodic Table.

Question

Philoid · Accepted Answer

The differences between Mendeleev’s Periodic Table and The Modern Periodic Table are

(i) The elements in Mendeleev’s Periodic Table were arranged by mass and the modern periodic table arranges elements by atomic number.

(ii) Mendeleev’s periodic table contains about 66 elements but modern periodic table contains presently 118 elements.