Compare and contrast the arrangement of elements in Mendeleev’s periodic Table and the Modern Periodic Table.

Question

1 Answer

answered May 14, 2017 by Rohit Singh (63.2k points)
selected Dec 16, 2018 by Vikash Kumar

Best answer

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	Elements having similar properties were placed directly under one another.	3	Elements having the same valence shell are present in the same period while elements having the same number of valence electrons are present in the same group.
4	The position of hydrogen could not be explained.	4	Hydrogen is placed above alkali metals.
5	No distinguishing positions for metals and non-metals.	5	Metals are present at the left hand side of the periodic table whereas non-metals are present at the right hand side.