Chapter U1.9, Problem 7E

Interpretation Introduction

(a)

Interpretation:

The two different versions of periodic table need to be represented by explaining similarity between them.

Concept introduction: There are two version of the periodic table −one of them proposed by Russian Chemist Dmitri Mendeleev’s known as the old Periodic table. Later on due to some demerits new form of Periodic table Modern form of the periodic table. A total of 118 elements is arranged in the form of a table. The periodic table has horizontal and vertical rows-Groups and Periods.

Answer to Problem 7E

Elements are arranged on the basis of atomic mass and atomic number in the two different periodic table. The old form of the periodic table has 7 periods and 8 groups but in modern Periodic table, 7 periods and 18 groups are present.

Explanation of Solution

In both forms of periodic table, elements are arranged in groups and periods.

Periodic table in which elements are arranged in increasing order to atomic mass is as follows:

The periodic table where elements are arranged in increasing order of atomic number is as follows:

Interpretation Introduction

(b)

Interpretation:

The two different versions of periodic table need to be represented by explaining difference between them.

Concept introduction: There are two version of the periodic table −one of them proposed by Russian Chemist Dmitri Mendeleev’s known as the old Periodic table. Later on due to some demerits new form of Periodic table Modern form of the periodic table. A total of 118 elements is arranged in the form of a table. The periodic table has horizontal and vertical rows-Groups and Periods.

Explanation of Solution

Elements are arranged on the basis of atomic mass and on the basis of the atomic number in two different periodic tables.

The noble gases or neon gases are present in group zero in the periodic table where elements are arranged in increasing order of atomic masses and they are present in group 18 when elements are arranged in increasing order of atomic number.