merits and demerits of periodic classification

The two-kingdom classification received considerable recognition from biologists and was in use for quite a long period of time. However, as more and more information started emerging on the various groups of plants and animals, this system of classification was found ..

Merits: s is based on every item of the data. s takes care of both positive and negative deviation. Demerits: s is some what not easy to understand. The extreme values unduly affect s..

Merits: - Mean deviation is easy to calculate. This measure is simple to understand. This can be calculated from any average. Its value is based upon all the (observations) items of the data. It is less affected by extreme observations. It gives us an idea about how the items are situated..

The five-kingdom classification has certain merits and demerits. However, it is largely the most accepted system of modern classification mainly because of the phylogenetic placing of different groups of living organisms. This system of classification..

In spite of the above advantages, Mendeleev's periodic table suffered defects as follows: The position of hydrogen was not correctly defined. It was placed in group I although it resembles both the group I elements - the alkali metals and the group VII elements-the halogens, in their p..

Although the long form of the period table has been able to help in systematic studying the elements to a great extent, it has some minor defects: Hydrogen resembles both the alkali metals and halogens. But it has been placed with the alkalis. The lanthanides and actinides have not ..

This is mathematically incomplete because it ignores negative signs. As it can be calculated from any average, it does not have certainty (i.e., it is not a well defined measure). Its use is very limited in statistical work..

Mean deviation is easy to calculate. This measure is simple to understand. This can be calculated from any average. Its value is based upon all the (observations) items of the data. It is less affected by extreme observations. It gives us an idea about how the items are situated in the..

It has enabled us to explain the laws of chemical combination. Dalton was the first person to recognize a workable distinction between the ultimate particle of an element (atom) and that of a compound (molecule)..

There are seven periods in the periodic table and each period starts with a different principal quantum number. The first period corresponding to 'n' = 1 consists of only two elements hydrogen (1s 1 ) and helium (1s 2 ). This is because the first energy shel..