Question

How is the long form of periodic table better than the Mendeleev Periodic Table?

Answer 1

We need to know that Mendeleev was a Russian Scientist who gave the Periodic Law in 18 century. After the discovery of Newland Law of Octave, Mendeleev made some changes and gave the new periodic table naming it as the Mendeleev Table.
The long form of periodic table refers to the table which consists of all the elements discovered.

Complete Answer:
Mendeleev gave the periodic Law and discovered the periodic table.
The periodic Law states that physical and chemical properties of every element is a periodic function of its atomic mass.
He arranged the elements in their increasing atomic mass.
Later when other elements were discovered they could not fit in the table.
Also hydrogen was not given the position.
Later when isotopes were discovered whose position was not given.
As the elements with the same property were given two different positions which became a drawback.
Then Henry Moseley gave another table stating that the atomic number should be the criteria for arrangement.
So, the periodic Law was rectified and is termed as: The physical and chemical properties of an element are periodic functions of their atomic number. The table is divided into rows and columns. The horizontal rows are called periods. The vertical columns are called groups.
We have to remember that there are 7 periods and 18 groups in the long periodic table also called the modern periodic table. Hydrogen is placed on the top of the table.

Note:
We need to know that isotopes are elements that have the same atomic mass but different atomic number. For example: Carbon has two isotopes termed as C12 and C14 isotopes.
The position of isotopes was not fixed in the table. Due to this the table was rejected. Further Henry Moseley made changes and gave the new periodic table on the basis of atomic number.