what are the achievements of mendeleev periodical table
Answers
Answer:
Achievements of Mendeléev’s periodic table
1) element with a slightly greater atomic mass were placed
before an element with a slightly lower atomic mass with an inverted sequence so as to group the elements with similar properties. For example, cobalt with atomic mass 58.9 was placed before nickel with atomic mass 58.7.
2)He left some gaps in the Periodic Table with the prediction of
existence of some elements that were not discovered at that time.
3) He named the future elements by prefixing a Sanskrit numeral, Eka (one) to the name of preceding element in the same group.
4) For instance, scandium, gallium and germanium, discovered later, have properties
similar to Eka–boron, Eka–aluminium and Eka–silicon, respectively.
5)Noble gases like helium (He), neon (Ne) and argon (Ar) were discovered
later as they are present in exceptionally low concentrations in the atmosphere due to their inertness.
________Answer_______
✒Mendeleev's Periodic Table :-
=>The physical and chemical properties of elements are periodic function of their atomic mass .
✒Achievements :-
- In order to adjust elements in his periodic table the sequence was inverted in which elements with slightly greater atomic mass were placed before the element with Lower atomic mass.
- for example:- Cobalt (Co) with atomic mass 58.93 and Nickel (Ni) with 58.71
- He left some gaps from the Undiscovered periodic table . He predicted the existence of some element that had not been discovered.
- He named them by prefixing Sanskrit numeral Eka(one) to the name of preceding element in the same group.
- for example:- Scandium,Gallium, Germanium discovered later has properties to Eka- Boron( Scandium) , Eka - aluminium (Gallium) , Eka -silicon (Germanium)
- Noble gases which were discovered later could be placed in new group without disturbing the existing order.
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