Question

List any three observation which passed a challenge to mendeleevs law

Answer 1

Controversial place of hydrogen

Wrong order of atomic mass

No place for nobel gases

Answer 2

The observation which posed a challenge to Mendeleev periodic table are ;
(1)Position of hydrogen in first group among metal through it is non metal
(2)Placing the element with higher atomic mass before the element with lower lower atomic mass
(3)No place were left in between two group to for isotopes .