Isotone Definition and Meaning

Isotones are atoms that have an equal number of neutrons but have different numbers of protons. E.g., ³⁷Cl₁₇, ³⁶S₁₆, ³⁹K₁₉, ⁴⁰Ca₂₀ and ³⁸Ar₁₈. 

All of these are isotones of 20 since all these contain 20 numbers of neutrons. Radioactivity and Nuclear energy depend on the imbalanced isotopes of such heavy elements for tapping the explosive power of the nucleus. 

Of this species nucleus, chlorine has 17 numbers of protons and 20 numbers of neutrons, while in contrast, potassium has 19 numbers of protons and 20 numbers of neutrons. Chlorine-37 and potassium-39 are also isotones. 

Isotones Differ in the Number of Protons

Isotones are that kind of atomic species in which two numbers of isotopes and atoms have the same number of neutrons but have different numbers of protons. That is why we call these atomic species as isotones. 

Now let us understand the difference between the number of protons in Isotones. Let us see some isotones and how they differ from each other in the number of protons.

Carbon-12 (¹²C), Nitrogen-13 (¹³N), and Oxygen-14 (¹⁴O)

All of these nuclides have six numbers of neutrons. But Carbon-12 has a total of six numbers of protons, Nitrogen-13 has a total of seven numbers of protons, and Oxygen-14 has a total of eight numbers of protons. 

These nuclei have the same numbers of neutrons, but they differ in their number of protons.

Oxygen-18 (¹⁸O), Fluorine-19 (¹⁹F), and Neon-20 (²⁰N)

These nuclei carry a total 10 number of neutrons, but these nuclei have a distinct number of protons. Oxygen-18 carries eight protons, whereas fluorine-19 carries nine protons, and the neon-20 carries ten protons. 

They are the same in their number of neutrons but very different in their number of protons.

Carbon-13 (¹³C) and Boron-12 (¹²B)

Both of these have seven numbers of neutrons. But carbon-13 has a total of six numbers of protons while boron-12 has five protons. These atoms have the same number of neutrons, but they differ by their total number of protons.

More About Isotones

In 1803, John Dalton put forward that all of these matter are breakable into tiny particles called atoms. 

Each of those atoms controlled the three elementary particles known as neutrons, protons, and electrons; scientists subsequently discovered all these elementary particles. They found the total number of protons, neutrons, and electrons in an atom which determines its size and mass number. 

There are so many different kinds of atomic species. They are known as isotopes, isobars, isoelectronic, and isotones.

Isotone is an atomic species where two or more atoms have the same neutrons but have different numbers of protons. 

Because of this similarity to the Greek for the word “same stretching”, the German physicist K. Guggenheimer formed the name isotone. He replaced the “p” in “isotope,” from “p” for the “proton” to “n” for the “neutron.

Examples of Isotones

Having two numbers of nuclides are known as isotones if these isotones consist of a similar number of neutrons N but have different numbers of proton Z.

Here are some examples of isotopes:

Carbon-13 (¹³C) and Boron-12 (¹²B)

Both of these have seven neutrons. However, carbon-13 has six protons while boron-12 has five protons. That is why these atoms are called isotones.

Chlorine-37 (³⁷Cl), Sulphur-36 (³⁶S), Potassium-39 (³⁹K), Argon-38 (³⁸Ar), and Calcium-40 (⁴⁰Ca)

All of these nuclei are examples of isotones. They all have 20 neutrons, but their number of protons does not match. All of these nuclei have different numbers of protons.

Carbon-12 (¹²C), Nitrogen-13 (¹³N) and Oxygen-14 (¹⁴O)

All of these nuclei have six numbers of neutrons. Carbon-12 has a total of six numbers of protons, Nitrogen-13 has a total of seven numbers of protons, and Oxygen-14 has a total of eight numbers of protons. Thus, they differ by their number of protons.

Fluorine-19 (¹⁹F),  Neon-20 (²⁰N), and Oxygen-18 (¹⁸O)

These nuclei carry a total 10 number of neutrons, but they have a different number of protons. Oxygen-18 carries a total eight number of protons, fluorine-19 carries a total nine number of protons, and the neon-20 carries total ten numbers of protons. 

Conclusion

Each of those atoms controlled the three elementary particles known as neutrons, protons, and electrons; scientists subsequently discovered all these elementary particles. They found the total number of protons, neutrons, and electrons in an atom which determines its size and mass number. There are so many different kinds of atomic species. They are known as isotopes, isobars, isoelectronic, and isotones. In this article, we understood that isotones are that kind of species or pairs of atoms that have the same number of neutrons, but they differ by their total number of protons. We have also discussed the examples of isotones. Example, ³⁷Cl₁₇, ³⁶S₁₆, ³⁹K₁₉, ⁴⁰Ca₂₀ and ³⁸Ar₁₈.