Question

What are the merits of Mendeleev’s periodic table?

Answer 1

Hint: The chemical properties of an element can be largely governed by the arrangement of the number of electrons present in the outermost shell of the element. According to Mendeleev, in the periodic table, the chemical elements are arranged in such a way that element properties are the periodic functions of atomic mass. But in the modern periodic table, the physical and chemical properties of elements are a periodic function of their atomic number.

Complete answer:
The important characteristics of Mendeleev’s periodic table are given as follows:
1. In the periodic table, the vertical columns are known as groups whereas the horizontal rows are known as periods.
2. The periodic table is composed of seven horizontal rows and eight vertical columns that means it consists of seven periods numbered as 1 to 7 and eight groups numbered as 1 to 8.
3. Each column in the periodic table consists of two sub columns in which elements that are similar are placed in the same sub-columns.
4. Group VIII represents transition elements whereas other groups are meant for normal elements.
5. The groups with similar physical and chemical properties are placed within the same group.
Some merits of Mendeleev’s periodic table are as follows:
1. It gave more focus to similarities in properties rather than to atomic mass while arranging the elements.
2. It led to the correction of the atomic mass of various chemical elements.
3. It could predict the properties and existence of three elements which have similar properties to boron, aluminium and silicon. The new elements predicted were isolated scandium, gallium and germanium and were initially named as Eka-boron, Eka-aluminium and Eka-silicon respectively.
4. Noble gases were introduced much later in the periodic table, As these molecules are inert in nature so it can easily be attached to the periodic table.

Note:
It is important to remember that although Mendeleev’s periodic table had many merits but it was rejected because, he arranged the elements on increasing order of their atomic mass and it is not a regular property from one element to another, Isotopes of the elements violated the Mendeleev’s periodic table and the does not have a certain values.