Chapter 6.1, Problem 1LC

Interpretation Introduction

Interpretation:

The earliest process of arrangement of elements by chemists is to be determined.

Concept Introduction :

The 18th and 19th centuries saw the discovery of many new elements, rendering obsolete the general division of elements into metals and non-metals. To find and group elements with related properties, several tests were carried out.

Answer to Problem 1LC

The characteristics of the elements were employed by early chemists to group them.

Explanation of Solution

German chemist J.W. Döbereiner, in 1829, published a classification known as Döbereiner's triads The Döbereiner's triads were an early attempt to group the elements based on their physical characteristics into logical order and sets.

Dobereiner's law of triads says that the atomic weight of the second element in a triad would be approximately equal to the averageof the atomic masses of the first and third elements in that triad.

One such triad is chlorine, bromine, and iodine. The mean of atomic masses of chlorine and iodine $\left(35.4531+126.90/2\right)=81.18\text{ amu}$ almost equal to the atomic mass of bromine $\left(70.904\text{ amu}\right)$ . Thus, these three elements show similar properties and can be grouped.

Conclusion

So, the physical properties of elements are used for organizing elements into some order or group.