Question

writes the merits and demerits of Mendeleev classification of element.


content quality answer, no spamming×××××

Answer 1

Hey there!!!

=>> In the Mendeleev's classification of elements, the elements are arranged in the order of increasing atomic weights. The Mendleev's periodic law states that the properties of the elements are a periodic function of their atomic weights.

=>> There were eight vertical columns (called groups) and Six horizontal rows (called periods or series) in the Mendeleev's periodic table. Defects in the Mendeleev’s periodic table were as follows:

Position of hydrogen is not justified.

Certain elements of higher atomic masses precede those with lower atomic weights (for example, cobalt was placed before nickle despite having higher atomic mass).

Isotopes are placed in the same position in the table. However, according to Mendeleev’s law, they should be placed in different positions

It is beacuse of the above shortcomings that Mendeleev's periodic table was not accepted as the correct classification of elements. 

=>> The advantages of Mendeleev's periodic table are :

1 Mendeleev's periodic law had predicted the existence of elements that had not been discovered that time.

2.This periodic table could predict the properties of several elements on basis of their position in periodic table.

3 It could accommodate noble gases when they were discovered.

Hope it helped!!!!☺️

Answer 2

$hey \: dear \: here \: is \: your \: answer$

⭐⭐<==================>⭐⭐


✯MERITS :

➊. he left proper gap for the undiscovered elements such as gallium, scandium and Germanium.

➋. he predicted the properties of several elements on the basis of their positions. gallium, scandium and Germanium discovered letter but the properties of these element decided first.

➌. he could accommodated the separate group for the noble gases and although they were not discovered at that time.



✯DEMERITS :


➊. the position of isotopes could not be explained.


➋. wrong order of atomic masses of some element could not be explain.
for example= the atomic mass of Cobalt is 58.9 and of Nickel is 58.7 so the according to increasing order of atomic masses Nickel must be come first and Cobalt little later.


➌. a correct position of hydrogen could not be assigned.
for example= the property of hydrogen resemble to the properties of chlorine and fluorine but hydrogen placed in the alkali metal group.


☺
$hope \: this \: helps \: u \: dear$
✌✌✌.