Chapter 17, Problem 20A

(a)

To determine

To Define: An isotope.

Explanation of Solution

Introduction:

Some elements have multiple number of naturally occurring isotopes.

The different forms of an element having different number of neutrons but the same number of protons are said to be isotopes of an element. Isotopes can be represented by their element symbol and then differentiated by the sum of neutrons and protons.

Conclusion:

Hence, the forms of the element having different number of neutrons and equal number of protons are called isotopes.

(b)

To determine

Two examples of isotopes.

Answer to Problem 20A

Two examples of isotopes are: Hydrogen and Carbon

Explanation of Solution

Introduction:

As explained in the part (a), the isotopes are the multiple forms of an element having different number of neutrons and the same number of protons.

There are three isotopes of hydrogen which can be written as:

  $\text{H}\text{, }\text{H},\text{H}$

There are three isotopes of carbon (carbon-12, carbon-13 and carbon-14) which can be written as:

  $\text{C}\text{, }C,\text{C}$

Conclusion:

Two examples of isotopes are: Hydrogen and Carbon