Chapter 15, Problem 11TE

To determine

The atomic masses present in the periodic table not a whole number

Answer to Problem 11TE

The atomic masses listed in the periodic table are not whole number because the atomic mass shown in the table is the average atomic mass of isotopes of all the elements of the periodic table.

Explanation of Solution

All the atoms of an element exist in many other similar forms with nearly same electronic configuration. These other similar forms of elements are isotopes and isobars. The properties of these other forms nearly same as the original element but due to small variation in the composition of the nucleus other forms exist in a small amount with the abundant form of the element.

The atomic mass of an element is defined as the average mass of all of its isotopes. The average atomic mass is generally in the form of decimals, so the atomic mass of all the elements shown in the periodic table is not whole number.

Conclusion:

Therefore, the atomic masses listed in the periodic table are not whole number because the atomic mass shown in the table is the average atomic mass of isotopes of all the elements of the periodic table.