Difference Between Protium Deuterium and Tritium

Main Difference – Protium vs Deuterium vs Tritium

Protium, Deuterium, and Tritium are isotopes of the Hydrogen element. Isotopes are different forms of the same element that are different from each other according to the number of neutrons they have in their nuclei. Therefore, isotopes have the same atomic number but different atomic masses. Due to this reason, isotopes have different physical properties but the chemical properties remain the same because the number of electrons present in isotopes is equal. Therefore Protium, Deuterium, and Tritium share some similarities as well as differences. The main difference between Protium Deuterium and Tritium is that Protium has no neutrons in its nuclei whereas Deuterium is composed of one neutron and Tritium is composed of two neutrons.

Key Areas Covered

1. What is Protium
      – Definition, Properties, and Abundance
2. What is Deuterium
      – Definition, Properties, and Abundance
3. What is Tritium
      – Definition, Properties, and Abundance
4. What are the Similarities Between Protium Deuterium and Tritium
      – Outline of Common Features
5. What is the Difference Between Protium Deuterium and Tritium
      – Comparison of Key Differences

Key Terms: Atomic Mass, Atomic Number, Deuterium, Isotopes, Neutron, Protium, Tritium

What is Protium

Protium is an isotope of Hydrogen that is composed of one proton and one electron. It is the most abundant form of hydrogen. The abundance of this isotope in the earth’s crust is about 99.9%. Protium has no neutrons in its nucleus. It is considered as the most stable isotope of hydrogen. Therefore, when we are normally talking about hydrogen, we are talking about Protium.

The atomic number of Protium is 1 due to the presence of one proton. The mass number of Protium is also 1 since there are no neutrons in the nucleus of Protium. The atomic mass of Protium is about 1.00794 amu. The symbol for Protium is ¹H. The electron configuration of Protium is 1s¹.

Protium can be found in nature as a diatomic gaseous form or as hydrogen in H₂O molecule. The bond between two atoms in the diatomic molecule has a higher bond dissociation enthalpy. This is mainly because these atoms are minute and they have complete electron configurations in the only orbital (s orbital) in their diatomic molecule form.

Difference Between Protium Deuterium and Tritium_Figure 1

Figure 1: Atomic Structure of Protium

The above image shows the atomic structure of Protium. Here, the proton is shown in the center of the atom (nucleus) and the electron is shown outside the nucleus in blue color.

What is Deuterium

Deuterium is an isotope of Hydrogen that is composed of one proton, one neutron, and one electron. The nucleus of Deuterium is composed of a proton and a neutron. The symbol for Deuterium is given as ²H. The atomic number of Deuterium is 1 and the mass number is 2. The atomic mass can be given as 2.014 amu. This is also a stable isotope of hydrogen but is less abundant. The abundance of Deuterium in the earth’s crust has been calculated as 0.015%. It is not radioactive since Deuterium is stable with one proton and one neutron in its nucleus.

Difference Between Protium Deuterium and Tritium_Figure 2

Figure 2: Atomic Structure of Deuterium

The occurrence of Deuterium can be either in gas phase or liquid phase. Deuterium exist as diatomic gases such as D₂ or HD (in combination with hydrogen). If not, Deuterium can be found as heavy water. Heavy water is composed of D₂O molecules. Most of the times, Deuterium act in a similar manner as Protium. But there are certain differences too. Due to the presence of the neutron, the atomic mass of Deuterium is as twice as Protium. Therefore, the bond length and bond energy are different from those of Protium. Moreover, ice made from heavy water will sink in liquid water due to high density (normal ice floats on liquid water surface).

There are some applications of Deuterium as well. In NMR spectroscopy, Deuterium included compounds are used as the solvent instead of compounds composed of Hydrogen. Then, the peaks given by hydrogen atoms of the analyte can be distinguished by the atoms of the solvent.

What is Tritium

Tritium is an isotope of hydrogen that is composed of one proton, two neutrons, and one electron. The symbol for Tritium is ³H. The atomic number of Tritium is 1 and the atomic mass of Tritium is 3. The mass can be given as 3.016 amu. This isotope of hydrogen is radioactive due to the presence of a high number of neutrons compared to the number of protons.

Tritium often undergoes beta decay. This produces Helim-3 and it releases a large amount of energy. The half life of Tritium has been calculated as 12.32 years. However, the abundance of Tritium on earth’s crust is very less.

Main Difference - Protium Deuterium and Tritium

Figure 3: Atomic Structure of Tritium

The above image shows the atomic structure of Tritium. The mass number of Tritium is 3 due to the presence of two neutrons (in red color) and a proton (in blue color).

Similarities Between Protium Deuterium and Tritium

Protium, Deuterium and Tritium are isotopes of hydrogen.
These isotopes are composed of 1 proton per nucleus.
All three are composed of 1 electron.

Figure 4: Protium Deuterium Tritium

Definition

Protium: Protium is an isotope of Hydrogen that is composed of one proton and one electron.

Deuterium: Deuterium is an isotope of Hydrogen that is composed of one proton, one neutron, and one electron.

Tritium: Tritium is an isotope of hydrogen that is composed of one proton, two neutrons, and one electron.

Abundance

Protium: The abundance of Protium is about 99.9%.

Deuterium: The abundance of Deuterium is about 0.015%.

Tritium: Tritium is found in very trace amounts.

Chemical Symbol

Protium: The symbol for Protium is ¹H.

Deuterium: The symbol for Deuterium is ¹H.

Tritium: The symbol for Tritium is ¹H.

Mass Number

Protium: The mass number of Protium is 1.

Deuterium: The mass number of Deuterium is 2.

Tritium: The mass number of Tritium is 3.

Atomic Mass

Protium: The atomic mass of Protium is 1.00794 amu.

Deuterium: The atomic mass of Deuterium is 2.014 amu.

Tritium: The atomic mass of Tritium is 3.016 amu.

Radioactivity

Protium: Protium is not radioactive.

Deuterium: Deuterium is not radioactive.

Tritium: Tritium is radioactive.

Conclusion

Protium, Deuterium and Tritium are three isotopes of hydrogen. Apart from these isotopes, there can be some other forms of hydrogen as well. But they are highly unstable due to the presence of a high number of neutrons. The main difference between Protium Deuterium and Tritium is that Protium has no neutrons in its nuclei while Deuterium is composed of one neutron and Tritium is composed of two neutrons.

References:

1.”Isotopes of Hydrogen – Boundless Open Textbook.” Boundless. Boundless, 20 Sept. 2016. Web. Available here. 02 Aug. 2017.
2.”Deuterium, Tritium, and Protium – Three Hydrogen Isotopes.” Quirky Science. N.p., 25 Mar. 2017. Web. Available here. 02 Aug. 2017.

Image Courtesy:

1. “Hydrogen” By Mets501 – Own work (CC BY-SA 3.0) via Commons Wikimedia
2. “H-2 atom” By ZYjacklin – Own work (CC0) via Commons Wikimedia
3. “Blausen 0528 Hydrogen-3 Tritium” By BruceBlaus – Own work (CC BY 3.0) via Commons Wikimedia
4. “204 Isotopes of Hydrogen-01” By OpenStax College – Anatomy & Physiology, Connexions Web site. Jun 19, 2013. (CC BY 3.0) via Commons Wikimedia