He left some spaces in his periodic table and boldly predicted the existence of few elements like silicon, germanium and gallium. When noble gases were discovered can be kept in a separate group without disturbing the existing order. Disadvantages:
He couldn't allocate a correct position to hydrogen
.
What are disadvantages of Mendeleev's periodic table?
- He was unable to locate hydrogen in the periodic table.
- Increase in atomic mass was not regular while moving from one element to another. …
- Later on, isotopes of elements were found which violated Mendeleev's periodic law.
What are the two advantages of Mendeleev periodic table?
1) Mendeleev left some gaps in his periodic table asn boldly predicted the existence of some elements that had not been discovered at that time. 2)
He placed an element with a slightly lower atomic mass
. The sequence was inverted so that elements with similar properties could be grouped together.
What are the advantages and disadvantages of modern periodic table?
It is
easy to remember and reproduce
. The systematic grouping of elements into four blocks; s, p, d and f has made the study of the elements more simple. The position of some elements which were misfit on the basis of atomic mass is now justified on the basis of atomic number.
What are the advantages of Mendeleev classification?
It
could predict the existence of other elements and could predict their properties so
, as to leave space in the periodic table. It could accommodate all the sixty elements discovered at that time and could accommodate the noble gases which, where discovered later.
What are the limitations of Newlands octaves?
- Newland could arrange elements only up to calcium, out of the total 56 elements known.
- After calcium, every eighth element did not possess properties similar to that of the first.
- Only 56 elements were known at the time of Newlands, but later several elements were discovered.
What are the disadvantages of periodic table?
- Position of hydrogen is not satisfactory, it can be placed either in group I or 17 group of the first period.
- It fails to accommodate lathanides and actinides in the main body of the periodic table. These are kept separately at the bottom of the periodic table.
Can you now say why Mendeleev?
Mendeleev
developed a Periodic Table of elements
wherein the elements were arranged on the basis of their atomic mass and also on the similarity on chemical properties. … On this basis he formulated a Periodic Law, which states that ‘the properties of elements are the periodic function of their atomic masses'.
What is the advantages of periodic table?
ADVANTAGES OF THE PERIODIC TABLE:
It is easier to remember the properties of an element if its position in the periodic table is known
. The periodic table has made the study of chemistry systematic and easy. It acts as an aid to memory.
What are the uses of Mendeleev's periodic table?
- Systematic study of the elements.
- Atomic weights of elements were determined with the help of periodic table. …
- Atomic weight of elements were corrected. …
- Discovery of new elements – In Mendeleev's periodic table two consecutive members differs by two or three units in the atomic weight.
What are uses of modern periodic table?
The modern periodic table is used
to organize all the known elements
. In the modern periodic table the elements are arranged in Increasing order of atomic numbers.
What are the defects of modern periodic table?
- Anomalous Pairs. The following pairs of elements don't follow the follow Mendeleev's Principles: …
- Grouping of chemically dissimilar elements. …
- Position of Isotopes. …
- Electronic arrangement. …
- Separation of chemically similar elements. …
- The position of hydrogen.
What is the law of modern periodic table?
Periodic Table: It is the table of chemical elements arranged in order of atomic number such that elements with similar atomic structure appear in the vertical columns. Modern periodic law: The Modern periodic law states “
The chemical and physical properties of elements are a periodic function of their atomic numbers”
.
Who proposed the law of octaves mention its one limitation?
John Newlands
, who was an English scientist, proposed the law of octaves in the year 1866. He arranged them in increasing order of atomic mass and noticed that every 8th element had properties same as that of the 1st element.
Why did the law of octaves fail?
The law failed because of the following reasons: 1
The law was applicable only upto calcium. It could not include the other elements beyond calcium
. ii With the discovery of rare gases it was the ninth element and not the eighth element having similar chemical properties. … State Newlands' law of octaves.
What are the limitations of dobereiner's classification?
- Dobereiner could find only three triads; . i.e total of 9 elements only.
- However the total number of elements were more than that of those encompassed in Dobereiner's Triad.
- Thus, Dobereiner's could not be classify most of the elements known at that time.
