Chapter 10, Problem 98A

Interpretation Introduction

Interpretation: The reason for one mole of carbon to have a smaller mass as compared to one mole of sulfur needs to be explained. Also, the reason for the different atomic structures of these elements needs to be explained.

Concept Introduction: For any one mole of a substance, its mass is equal to the molar mass of the compound/molecule of the substance. Here, in 1 mol of all the substances, there are $6.022\times {10}^{23}$ formula units of the substance.

Explanation of Solution

In the periodic table, carbon and sulfur belong to different group numbers; thus, they belong to a different family. The number of atoms of carbon and sulfur is the same in 1 mol as it is according to Avogadro’s law but both elements cannot have the same mass as they have different atomic masses. Here, the carbon atom belongs to group 14 and the sulfur belongs to group 16. On moving from left to right in periods, atomic mass increases. The atomic mass of carbon is 12 g/mol and that of sulfur is 32 g/mol. Thus, in 1 mol the mass of the carbon atom is 12 g and that of the sulfur atom is 32 g. Therefore, 1 mol of carbon atom has a smaller mass than 1 mol of sulfur.

The atomic structure of carbon and sulfur is different because they have different atomic numbers. Due to different atomic numbers, the number of electrons is different in both elements and the arrangement of electrons in the atomic orbital is also different.

The atomic number or number of electrons in carbon and sulfur atoms is 6 and 16 respectively. Since the number of electrons in sulfur is greater than in carbon, it has a bigger size as compared to carbon and both have different atomic structures.