Isotopes and Isobars

Introduction

Isotopes and isobars are two significant associated with the elements present in the periodic table. Isotopes have an equal atomic number, but varied mass number and isobars have an equal mass number but a varied atomic number.

The radiochemist Frederick Soddy in the year 1913 introduced the idea of isotope by bringing the concept that elements may also have one or more extra mass numbers. Then the scientist Alfred Walter Stewar in the year 1918 discovered the existence of isobars, which means an identical mass number or atomic weight.

The discovery of Isotopes and isobars has contradicted several theories that have been existing for a long time. According to Dalton's theory of atoms, the elements that contain identical atomic numbers will have similar properties. But the discovery of Isotopes proved that atoms with identical atomic numbers but with dissimilar mass numbers will also show different properties.

Atomic Number

The elements present in the periodic table are arranged based on the increasing order of atomic numbers. Every element present in our universe has a particular atomic number that can be used for the identification of these elements. The atomic number is the number of protons present in the nucleus of an element.

The number of protons is different for different elements and is the reason for its identification based on the atomic numbers. It is represented with the help of the letter; Z. atomic numbers also talks about the number of electrons since the number of protons and electrons are always the same for elements. The number of electrons and protons is the same only for neutral atoms. For charged species, this number may vary. For example, the atomic numbers of the element carbon is 6, so it contains 6 protons and electrons.

Atomic Mass Number

The mass number or atomic mass number is also another important term that has a close association with the chemical and physical properties of elements. For a single atom, the mass number is calculated, or it is the addition of the proton number and neutron number present in an atom. The mass number of carbon is 12 and is obtained by the addition of neutron and proton (6). The mass number is represented with the help of the letter, A. The atomic mass or mass number gives the idea of the weight of an atom.

Isotopes

Isotopes are a variant of elements with varied mass number. But they have identical atomic numbers. Since the mass number is obtained by the addition of a proton and the neutron number, the quantity that is different in the case of isotopes is the neutron number. And these isotopes may be naturally obtained or maybe artificially synthesized. Most of the natural isotope found on the earth is stable comparatively artificial isotopes synthesized by humans. Almost all the elements present in the periodic table have been found to have isotopes. There are about 256 isotopes for the elements discovered so far. Artificial isotopes undergo radioactive decay too.

Examples

Some of the examples of isotopes are pointed out below.

• The isotopes of carbon are $\mathrm{^{12}_{6}C\:,\:^{13}_{6}C\:and\:^{14}_{6}C}$

• The isotopes of hydrogen are $\mathrm{^{1}_{1}H\:,\:^{2}_{1}H\:and\:^{3}_{1}H}$

• The isotopes of Iodine are $\mathrm{^{127}_{53}I\:and\:^{131}_{53}I}$

• The isotope of Boron is $\mathrm{^{1}_{1}B\:and\:^{1}_{1}B}$

Isobars

Isobar is also an element associated with elements and atoms. Isobar includes an element that has an equal mass number but a different atomic number. As the atomic number is different for each member of the isobar the chemical properties of this class are different. Since the number of protons, and electrons are different. But Isobars have been found to show similar physical properties. They are used in the nuclear chemistry and medical field for several uses.

Examples

There are many examples of isobars. Some of them are pointed out below.

• $\mathrm{^{40}_{18}Ar\:,\:^{40}_{19}Kr\:and\:^{40}_{20}Ca}$ are examples of isobars with the same mass number

• $\mathrm{^{14}_{6}C\:and\:^{14}_{7}N}$ are examples of an isobar with the same mass number 14.

• $\mathrm{^{58}_{26}Fe\:and\:^{58}_{28}C}$ are also an example of an isobar with a mass number of 58.

• $\mathrm{^{37}_{17}Cl\:and\:^{37}_{18}Ar}$ are other examples with the mass number 37.

Write the difference between Isotopes and Isobars.

The difference between isotopes and isobars is tabulated below.

Isotopes	Isobars
Atomic numbers are equal.	Atomic numbers are varied.
They are just identical chemical elements with different forms.	They are two entirely different chemical elements with similarities in mass number.
They have almost identical chemical and physical properties.	They have different chemical properties but have the same physical properties.
For a family of isotopes or groups, all the members have the same atomic number.	For a family of isobars or groups, all the members have distinct atomic numbers.
The position of isotopes in the periodic table is similar.	They have a dissimilar position in the periodic table.
The atomic masses are different.	They have identical atomic mass.
The number of neutrons is different.	The number of neutrons is also different.
The atomic masses are different.	They have identical atomic mass.

Aloha2009, N14-C14, CC BY-SA 3.0

Conclusion

Isotopes and isobars are two important terms associated with atoms present in the elements. They are important in explaining several properties of atoms. Atomic numbers and mass numbers are needed for the explanation of isotopes and isobars.

The atomic number gives the number of protons present in an element while the mass number gives the entire mass of an atom by adding the number of protons, neutrons, and electrons. Isotopes are a class of elements with equal atomic numbers while the isobars are the ones with equal mass numbers. Among Isotopes and isobars, Isotopes are the same chemical element with a variant, but isobars are entirely different chemical elements.

FAQs

1. What is the application of isotopes in the agricultural sector?

In the agricultural sector, the isotope of phosphorus is used for studying the absorption tendency of plants. The isotope, phosphorus-32 is used for this.

2. How do industries make use of isotopes?

There are many industries useful Isotopes for various applications. For example, in the food industry, the isotope of Cobalt, Cobalt-60 which produces gamma rays have been used for killing microorganisms present in the food. In the plastic manufacturing industry, the isotope of Krypton, Krypton-85 is used for managing the thickness of plastic compounds.

3. What are the applications of isobars?

Isobar is also employed in many applications. One of the isobars of Cobalt is used for treating cancer, the isobars of Uranium are used in the nuclear reactors, for goitre treatment the isobar of iodine is used, for the treatment of leukaemia the isobar of phosphorus is used, etc.

4. Could isobar be easily adjusted in the Mendeleev periodic table?

No, the presence of a dissimilar mass number of isobars is the reason. The arrangement of elements in Mendeleev's periodic table is based on the atomic number but if it is based on the mass number this will be possible.

5. Give examples of isotones?

Isotones possess an equal number of neutrons. In $\mathrm{^{39}_{19}K\:,\:^{36}_{36}S\:.\:^{37}_{17}Cl\:and\:^{38}_{18}Ar}$ has 20 neutrons each.