Question

descrbe mendeleeffs modified periodic table. write its defect and advantages.​

Answer 1

Advantage of Mendeleev Periodic Table :- 1.He left blank  Places which help scientist to discover new element2.When Noble gasses was discovered Hel could add  it to periodic table without any major changle  3.He predicted the property of new element Disadvantages :- 1. Couldn't explain position of Hydrogen  2.Couldn't answer the question "Can we have an element with atomic mass 3 between Hydrogen and Helium  3 He placed cobalt before Nickel though Cobalt has more mass