Chapter 6, Problem 98A

Interpretation Introduction

Interpretation:

The reason for the placement of noble gases on the right of the modern periodic table making sense needs to be explained.

Concept introduction:

According to Mendeleev’s periodic law the elements are arranged according to their atomic weights.

Answer to Problem 98A

In the Mendeleev’s periodic table, noble gases are placed on the left of the table. But placement on the right of the modern periodic table makes more sense because noble gases have 18 valence electrons.

Explanation of Solution

In modern periodic table there are 18 groups. These groups are placed according to the number of valance electrons from group 1 to group 18. Noble gases have 18 valence electrons. In this table, noble gases are placed to the right side of periodic table. Thus to obtain an octet, it is easy to decide how many electrons must lost or gained.

Conclusion

Noble gases have 18 valence electrons thus placement on the right of the modern periodic table makes more sense.