Question

In Mendeleev’s periodic table few elements that are chemically similar are placed in the same groups.
A.True
B.False

Answer 1

Hint:We know that Mendeleev’s periodic law states that the elements properties are the periodic function of the atomic masses of elements.

Complete step by step answer:We must remember that the Mendeleev grouped sixty three elements based on the increasing order of their relative atomic mass. We call this as Mendeleev’s periodic table. He separated the table into eight columns and seven rows. The columns were called as groups and the rows were known as periods.
Explanation:
The normal elements were located in Groups I to VII, transition elements were present in Group VIII.
Groups I to VII have been classified to two sub-groups, whereas three elements were meant to be Group VIII.
Periods from 4th to 7th were divided into first series and second series.
Elements showing similar properties were located in the same group. Example: Lithium, rubidium, potassium were present in the first group.
Two common formulas: One for oxides and other one for hydrides were given for elements present in each group of the periodic table. The formula for oxides is ${R_2}O$ and the formula for hydrides is $RH$ of elements present in the first group.
Oxides of potassium, sodium etc would have formula as ${K_2}O$ ,$N{a_2}O$ etc.
The given statement in Mendeleev’s periodic table certain elements which are chemically similar are found in the same groups is true.
Therefore, the option (A) is correct.

Note:As we know that the merits of the Mendeleev periodic table is that some gaps were left for the elements that are to be discovered. So, if a certain new element is discovered, it can be placed in a new group without disturbing any present group. Some of the demerits are that the position of hydrogen was missing. The increase in atomic mass was not systematic when moving from one element to another. Isotopes violated the Mendeleev’s periodic law.