Chapter 6, Problem 80A

Interpretation Introduction

Interpretation:

The reason for the atomic masses in Mendeleev’s table different from today’s values needs to be explained.

Concept introduction:

Elements were grouped in Mendeleev's periodic table based on the fundamental characteristics, atomic mass, and chemical properties. After examining the properties of each element, Mendeleev found that atomic mass was periodically related to the properties of the elements. In today’s periodic table, elements are arranged in order of their increasing atomic number and each element is indicated by its chemical symbol.

Answer to Problem 80A

The arrangement of Mendeleev’s periodic table was related to the atomic ratios in which elements produced oxides, binary compounds with oxygen, while the modern periodic table is organized by the atomic numbers, that is, protons number found in a particular element.

Explanation of Solution

Mendeleev’s periodic table calculated atomic masses from the mass of atoms and Avogadro’s number. In modern periodic table, atomic masses were obtained accurately from the isotopic masses. Hence, the values of the atomic masses in Mendeleev’s table are different from today’s values.