Chapter 10, Problem 120A

Interpretation Introduction

Interpretation: To determine how can the periodic table be used to infer the number of valence electrons of an atom.

Concept Introduction: Chemical elements are listed in a table called a periodic table, which is often arranged in rows according to atomic number so that elements with similar atomic structures appear in vertical columns.

Answer to Problem 120A

The number of valence electrons tells about the group of the atom in the periodic table.

Explanation of Solution

A periodic table element's column can be used to determine its main group number. For instance, carbon, which belongs to group 4, has four valence electrons. Group 6-member oxygen has six valence electrons.

The quantity of valence electrons in an element determines its position in the periodic table as,

For instance

The electronic structure of sodium, Na (atomic number 11), is as follows.

2 electrons in the first shell

8 electrons in the second shell

1 electron in the third (valence) shell

Since sodium has a valence electron of 1, it belongs to group 1 of the periodic table.

As a result, an element's position in the periodic table is related to the valence electron(s) that it has in its atomic shell.