Chapter U1.14, Problem 2E

Interpretation Introduction

Interpretation:

Relationship between atom and isotope is to be explained.

Concept introduction:

All matter is made up of small particles called atoms. Atoms have subatomic particles like protons, electrons and neutrons. Atoms with same number of protons but different number of neutrons are called isotopes. An element may have one or more isotopes.

Answer to Problem 2E

Atoms are basic units of matter. They are the smallest particles that have the same identity of an element. All atoms of an element are same in the number of protons and electrons that they have. Some atoms of an element may have different number of neutrons. Such atoms are called isotopes.

Isotopes are basically same as atoms but only different versions of elements. So isotopes are elements with same atomic number but different mass number. They are like a pair of identical twins with lot of similarities but only one difference (number of neutrons).

Explanation of Solution

An atom is a basic unit of an element. An element has many atoms. All atoms of an element are nearly identical. However, some atoms of an element may differ in their atomic masses. Such atoms have different number of neutrons in their nuclei. Such atoms are called isotopes.

A naturally occurring element is made up of one or more isotopes. Some isotopes are found in abundance while some are present in very small amount in a known sample of the element.

Hence, one can say that an atom and an isotope of an element are like a pair of identical twins. Both have same number of protons and electrons. Hence their atomic numbers are same. They differ only in their atomic masses. Atoms of different isotopes of an element are basically atoms of the same chemical element. They will form similar compounds.

Example: Carbon has three isotopes; carbon - 12, carbon - 13 and carbon - 14. Most of the carbon atoms found in nature are carbon - 12. Out of 100 carbon atoms, it is quite likely to find one carbon - 13 atom and rarely a carbon - 14 atom. Structure wise they differ only in the mass of their nuclei.

Conclusion

Most of the naturally occurring elements have isotopes. Atoms or isotopes mean the same thing. Chemically they behave in the same manner. Only they have different number of neutrons, so their mass numbers or atomic masses are different.