Chapter 12, Problem 105A

Interpretation Introduction

Interpretation:

The chemist who has produced first widely used and accepted periodic table needs to be identified.

Concept introduction:

A periodic table is explained as a table showing the arrangement of elements in order of increasing atomic number. A modern periodic table has 18 groups and 7 periods. All the elements present in the same group show similar chemical and physical properties.

Answer to Problem 105A

Correct Answer: Option (a) Dimitri Mendeleev.

Explanation of Solution

Reason for correct option:

In 1867, Dimitri Mendeleev published his book principles of chemistry in which he attempts to classify elements depending on their chemical properties. The pattern led him to postulate a periodic table in which he shows the complete arrangement of all the known elements till then. After that, he made an extended version of the periodic table when more elements are discovered. In his periodic table, he has arranged elements on increasing order of their atomic weights. Elements with similar atomic weights exhibit similar chemical properties.

Conclusion

Reason for incorrect option:

The other scientist contributed to the periodic table but the accepted periodic table was produced by Dimitri Mendeleev. The contribution of other scientists is explained as follows:

Henry Moseley has discovered the atomic number of each element with the help of X-rays leading to an appropriate arrangement of elements in the periodic table.

John Newlands has proposed the law of octaves. According to this law, when elements are arranged in order of their atomic weights and an element has a similar property to every eighth element present in the periodic table.

The periodic table proposed by Mendeleev is followed by Lothar Meyer and he also proposed his periodic table. Both have arranged elements with respect to the atomic weight of elements and proposed that there is a reoccurrence of some properties that takes place periodically. The Meyer’s periodic table is based on atomic volume or molar volume. The atomic volume can be determined by dividing atomic mass by density. This periodic table proposed by Meyer is not further accepted and Mendeleev becomes the first scientist to propose a periodic table.