compare and contrast the arrangement of elements in 'mendeleev's periodic table and the modern periodic table

 

Asked by pchandrakala20 | 22nd Apr, 2020, 09:57: AM

Expert Answer:

Mendeleev's Periodic Table Modern periodic Table
1.Elements are arranged in the increasing order of their atomic masses. 1. Elements are arranged in the increasing order of their atomic numbers.
2.There are a total of 7 groups (columns) and 6 periods (rows). 2.There are a total of 18 groups (columns) and 7 periods (rows).
3. The position of hydrogen could not be explained. 3. Hydrogen is placed above alkali metals as it has one valence electron.
4.No distinguishing positions for metals and non-metals was assigned. 4.Metals are present at the left hand side of the periodic table whereas non-metals are present at the right hand side.

Answered by Ramandeep | 22nd Apr, 2020, 10:37: PM