Radius Of Hydrogen Atom

Radius of hydrogen atom is 120 pm. Niel Bohr developed the Bohr Atom Model. This discovery was made after he analyzed the trend of the periodic table.

Radius Of Hydrogen Atom

:eight_pointed_black_star: About Hydrogen

:small_red_triangle_down: Fast Facts

Element Hydrogen
Atomic number (Z) 1
Group Group 1: hydrogen and alkali metals
Period period 1
Block s-block
Electron configuration 1s1
Electrons per shell 1
Melting point (H2) 13.99 K ​
Boiling point (H2) 20.271 K ​
Triple point 13.8033 K, ​7.041 kPa
Critical point 32.938 K, 1.2858 MPa
The heat of fusion (H2) 0.117 kJ/mol
The heat of vaporization (H2) 0.904 kJ/mol
Molar heat capacity (H2) 28.836 J/(mol·K)

Hydrogen is the most abundant chemical in the universe, making up nearly 75% of all matter. The Sun is made up of mostly plasma hydrogen. Most hydrogen on Earth is in the form of water or organic molecules. Each atom of 1H has one proton, one electron, and no neutrons.

Protons, the hydrogen nuclei, formed in the first second. It was 370,000 years later when the plasma had cooled sufficiently for electrons to remain bonded to protons, that neutral hydrogen atoms appeared throughout the cosmos.

Steam reforming natural gas is used in industrial production, with less energy-intensive processes such as water electrolysis. The two major applications of hydrogen are in fossil fuel processing (e.g., hydrocracking) and ammonia manufacturing (primarily for the fertilizer industry). Hydrogen embrittles various metals, hindering pipeline, and storage tank design.

:eight_pointed_black_star: Phases Of Hydrogen

  • Plasma hydrogen

  • Gaseous hydrogen

  • Metallic hydrogen

  • Liquid hydrogen

  • Solid hydrogen

  • Slush hydrogen

When used in ionic compounds, hydrogen can be either a negatively charged (anion) or positively charged (cation) species, represented by the symbol H+. The H+ cation is a proton (symbol p), but in aqueous solutions and ionic compounds, it is charged by surrounding polar molecules or anions.

Because the Schrödinger equation can only be solved analytically for hydrogen, its energetics and chemical bonds have been studied extensively in the development of quantum mechanics.

Acids on metals created hydrogen gas for the first time in the early 1600s. Henry Cavendish discovered in 1766–81 that hydrogen gas is a distinct chemical that generates water when burned, a quality later called after it: hydrogen means “water-former” in Greek.


Hydrogen is nonmetallic and forms a single covalent link with most nonmetallic elements, generating water and practically all organic molecules. Because acid-base interactions frequently entail proton exchange between soluble molecules, hydrogen is vital.

:eight_pointed_black_star: Radius Of Hydrogen Atom Formula

Physicist Niels Bohr (1885–1962) of Denmark drew on Rutherford’s planetary atom model right away in his work. In 1912, Bohr visited Rutherford’s laboratory and became convinced of its legitimacy. As soon as he got back to Copenhagen in 1913 and started working on his theory of hydrogen and the planetary model, it was published. There have been numerous unanswered concerns regarding atomic properties for decades.

To characterize emission spectra, certain formulae have been developed. With just one electron, hydrogen has a pretty basic spectrum, as you might anticipate. Infrared (IR), visible (Visible), and ultraviolet (UV) spectral lines were identified in the hydrogen spectrum. They are named after researchers who spent a lot of time looking at them.

First created for his series, Balmer’s formula was subsequently discovered by varying values of nf to describe all other series. Initially, Bohr was the only one to see the bigger picture. In physics, we observe the importance of both experiment and theory. An equation that matched the experimental data had been developed; nevertheless, the theoretical underpinnings remained a mystery.


A lot was known about atoms, but the physical rules that govern them had yet to be adequately defined. The atomic spectrum of hydrogen was described by Bohr’s theory, which introduced new and widely applicable quantum mechanics concepts.

:eight_pointed_black_star: What Is Bohr Radius?

What is Bohr Radius?

Symbol a0 or rBohr
Named after Niels Bohr
SI units 5.29×10−11 m
natural units 3.27×1024 ℓP

Atomic physics uses the Bohr radius as a physical constant. An electron’s distance from a hydrogen atom’s nucleus is explained. The Bohr radius is denoted by the sign ao or rBohr. The Bohr model was devised by physicist Niels Bohr, whose name is given to this constant.

In 1913, Niels Bohr proposed his Bohr model of atomic structure. According to him, electrons are attracted to the nucleus by electrostatic forces and move about it. A reduction of the Planck constant to an integer shows that electrons have several kinds of orbital angular momentum. Because it is the most basic atom, hydrogen was chosen by Bohr. One electron revolves around the nucleus, he discovered.

Current evidence suggests that this notion is simplistic. According to him, the electrons are encircled by orbicular probability zones, which resemble shells, and they move about the nucleus as a result. However, the Bohr radius is quite significant. There is a statement in there that says that the lowest average atom radius may generally be attained by a neutral atom.

When an electron is in the ground state, its orbit around the nucleus of a hydrogen atom has a mean radius denoted by a Bohr radius (lowest-energy level). It is a physical constant that the radius is 5.29177 x 10 -11 meters in length (m). 5.29177 x 10-9 cm (cm) or 0.0529177 nanometers (nm) is the measurement (nm). This span is comparable to 1/10,000th of a blue visible light ray’s wavelength.


The Bohr model of the atom was proposed by Danish physicist and philosopher Niels Bohr. Small, compact nuclei with positively and negatively charged electrons make up the atoms, according to his theory. The electrons are circling the nuclei in circular motions.

:eight_pointed_black_star: Radius Of Hydrogen Atom Derivation

Bohr’s Solution For Radius Of Hydrogen Atom

With the use of some new ideas, Bohr was able to come up with an equation that could be used to calculate the hydrogen spectrum. When it comes to electron-atom orbitals, we refer to them as “quantized” orbits since only a limited number of possible configurations are allowed.

When an electron takes in energy, it moves into a higher orbit; when it emits energy, it moves into a lower orbit. Quantization of the orbits results in discrete spectra of energy absorption and emission. One of the basic techniques of moving energy into and out of atoms is photon absorption and emission.

  • The electron’s energy changes when it goes from one orbit to the next, and this is used to explain how the photons’ energies may be quantized. This is written as E = hf = Ei Ef in equation form.

  • These are the five concentric circles that make Bohr’s planetary model for an atom. There is an increase in circle radii as one moves outward. Labels E sub one, E sub-two, and up to E sub, I have been placed on the circles in this pattern.

  • Between the first and final orbits, hf is the amount of energy received or expelled by the photon. The involvement of energy in orbital changes is a reasonable (i.e., predicted from our everyday experience) conclusion. The space shuttle, for example, needs a burst of power to ascend to a new altitude.

  • Quantization of atomic orbits is not something that is anticipated. Satellites and planets, which may be in an orbit with the right amount of energy, are not affected by this.

An illustration of the energy level is presented. Several horizontal lines may be seen in this image. Energy levels grow from bottom to top as the lines are labeled as n equals one, then n equals two, then n equals infinite. From the bottom to the top, the spacing between the lines gets smaller. Electrons migrate from n equals four to n equals two via a vertical arrow.


Bohr was able to figure out how to compute the energies of hydrogen’s electron orbitals because of his ingenuity. Although it has been improved upon, this was an essential initial step that deserves to be mentioned again because it accurately describes many properties of hydrogen. The angular momentum L of an electron in its orbit, according to Bohr, is quantized, i.e., it only has discrete values when considering circular orbits.

:eight_pointed_black_star: Rutherford’s Failed Radius Of Hydrogen Atom Theory

Rutherford's Failed Radius Of Hydrogen Atom Theory

Hans Geiger and Ernest Marsden had discovered that the scattering of atoms by particles could be explained by the theory of atoms provided by Ernest Rutherford. Helium nuclei (-particles) were fired at gold foils in these tests.

  • A majority of the particles did not disperse; they simply went through the thin metal foil undetected. Some of the dispersed few moved backward as if they were repulsed. The foil must include heavy particles to do this reverse scattering. This is exactly what happens when a -particle collides with one of these hefty particles.

  • The nuclei of the atoms must occupy just a tiny portion of the atom’s entire volume since most of the -particles do not disperse. Particles with very little mass must fill the vast majority of the space. They are the electrons that surround the nucleus, which is why they are called electrons.

  • The electron was posited to be circling the nucleus to keep it from collapsing. Change in velocity can be achieved by applying the Coulomb force (described in more detail below), exactly as a string or gravity would do to keep a ball in a circular orbit around your head. Gravity and Coulombic interactions have a lot in common, and this shows that this approach is a reasonable one.

  • A loss of energy occurs when an electron emits radiation. The radius of a particle’s orbit shrinks as it loses energy. The electron’s orbital frequency rises to conserve angular momentum.

As the electron falls near the nucleus, its frequency rises steadily. With a continuous spectrum, rather than discrete lines, it’s possible to see changes in electron frequency as well as emission frequency], which are the same. For this collapse to take place, one needs to figure out how long it takes.


The Rutherford model has a few flaws at its core. Because of the Coulomb force, an atom with a positive nucleus and negative electrons should collapse due to the attraction between them.

:eight_pointed_black_star: Triumphs And Limits Of The Radius Of Hydrogen Atom Theory

Bohr accomplished what no one had before. While he was describing hydrogen’s wavelength, he also properly computed its mass. His concepts may be applied to a wide range of situations. All atoms and molecules have a fixed number of electron orbital energies.

Quantities of angular momentum exist in the hydrogen atom theory. Instead of spiraling into the nucleus as predicted by classical theory (accelerated charges radiate, causing electron orbits to degenerate rapidly, causing matter to collapse), the electrons sit on the nucleus. These are significant victories.

During the development of quantum physics, it became obvious that there are no well-defined orbits but rather a cloud of probability. Bohr’s hypothesis also failed to explain why, upon closer inspection, some spectral lines seem to be doublets (split in two).

However, it is important to keep in mind that Bohr did not fail when it came to quantum mechanics in hydrogen atom theory. On the contrary, his discoveries paved the way for subsequent advancements in atomic physics by providing a solid platform for future research.


However, Bohr’s hypothesis has several limitations. Even a two-electron helium atom can’t be used since it’s too complex. We refer to Bohr’s model as semiclassical. Assumed to be simple circular routes, the orbits are quantized (nonclassical) (classical).

:eight_pointed_black_star: Production Of Hydrogen

Radius Of Hydrogen Atom

Chemical and biological laboratories create H2 as a by-product of other processes; industry produces H2 through the hydrogenation of unsaturated substrates, and nature produces H2 as a mechanism of expelling reducing equivalents in biochemical reactions.

:small_red_triangle_down: Electrolysis Of Water

Using electricity to electrolyze water is a straightforward technique of creating hydrogen. Water is passed through an electrochemical cell, which results in the formation of gaseous oxygen at the anode and gaseous hydrogen at the cathode.

It is common to practice using platinum or another inert metal as the cathode when generating hydrogen for storage purposes. The presence of oxygen is desired to aid the combustion process if the gas is to be burned on-site, and as a result, both electrodes would be built of inert materials. (For example, iron would oxidize, reducing the quantity of oxygen emitted by the reaction.)

:small_red_triangle_down: Methane Pyrolysis

The creation of hydrogen from natural gas methane pyrolysis is a relatively new one-step technique that emits no greenhouse gases. Increasing the volume of hydrogen produced using this technology is critical to enable quicker carbon reduction through the use of hydrogen in industrial operations, fuel cell electric heavy truck transportation, and gas turbine electric power generation.

Melting a metal catalyst at high temperatures (1440 K, 1065 °C, or 1950 degrees Fahrenheit) causes methane CH4 to bubble up through the metal catalyst. As a result, the methane is converted into hydrogen.

:small_red_triangle_down: Serpentinization Reaction

During the process of serpentinization, hydrogen (H2) is created in deep geological settings that are far apart from the Earth’s atmosphere. Water protons (H+) are reduced by ferrous (Fe2+) ions given by fayalite during this process (Fe2SiO4).

:small_red_triangle_down: Metal-acid

Many metals react with water to produce hydrogen, although the rate at which hydrogen is produced varies depending on the metal, the pH of the water, and the presence of alloying substances in the water.

The most prevalent cause of hydrogen evolution is the presence of acids. Aluminum, zinc, manganese, and iron are among the metals that react rapidly with aqueous acids, including the alkali and alkaline earth metals.

:small_red_triangle_down: Industrial Methods

Hydrogen is frequently created utilizing water steaming in conjunction with some transmission of natural gases, which requires the separation of hydrogen from hydrocarbons at extremely high temperatures. Steam reforming accounts for 48% of total hydrogen generation.

Commercial bulk hydrogen is often generated by the steam reforming of natural gas, which results in the release of greenhouse gases into the atmosphere or the capture of greenhouse gases through the use of carbon capture and storage (CCS) for climate change mitigation. Steam reforming, commonly known as the Bosch process, is a method of producing hydrogen that is widely employed in the industrial production of gas.

:small_red_triangle_down: Thermochemical

Water splitting may be accomplished by the application of more than 200 thermochemical cycles. There have been several of these cycles studied for their potential to produce hydrogen and oxygen from water and heat without the use of electricity.

These cycles include the iron oxide cycle, the cerium(IV) oxide/cerium(III) oxide cycle, the zinc zinc-oxide cycle, the sulfur-iodine cycle, the copper-chlorine cycle, and a hybrid sulfur cycle. Several laboratories are working on thermochemical ways to manufacture hydrogen from solar energy and water. These facilities are located in France, Germany, Greece, Japan, the United States, and other countries.


Transferring reducing equivalents from pyruvate fermentation to water results in hydrogen gas production. The hydrogen cycle refers to the natural cycle in which organisms produce and use hydrogen. Because of its small weight, hydrogen is the 3rd most common element by mass in the human body, despite having the most atoms.

:eight_pointed_black_star: Isotopes Of Hydrogen

In nature, hydrogen exists in three isotopes: 1H, 2H, and 3H. There have been laboratory syntheses of very unstable nuclei (4H to 7H) that have not yet been detected in nature.

  • 1H: Over 99.98 percent of the world’s hydrogen may be traced back to the most prevalent hydrogen isotope, 1H To describe the nucleus of this isotope, the formal word “protium” is employed, which is descriptive but not widely used. Stable isotopes are all unique in that they lack neutrons; see diproton for further information.

  • 2H: Deuterium, the other stable hydrogen isotope, has one proton and one neutron in its nucleus. Deuterium is assumed to have been created and has remained in the cosmos ever since. In terms of toxicity, deuterium does not pose a substantial threat.

  • 3H: The nucleus of 3H, or tritium, has one proton and two neutrons. It has a half-life of 12.32 years before disintegrating into helium-3 by beta decay. Because of its high radioactivity, it may be employed in luminous paint and timepieces. The minimal amount of radiation is blocked by the glass.

Cosmic rays combine with atmospheric gases to generate small quantities of tritium, which has also been released during nuclear weapons testing. A nuclear fusion process uses it, as does isotope geochemistry, as well as specialized self-powered illumination. Biological and chemical labeling investigations have also employed tritium as a radiolabel.

Heavy water is water that contains deuterium molecules instead of hydrogen atoms. Non-radioactive labels such as deuterium and its derivatives are employed in chemical investigations and as solvents in 1H-NMR spectroscopy. Nuclear reactors employ heavy water as a coolant and a neutron moderator. Additionally, commercial nuclear fusion might use deuterium as one of its fuels.

Deuterium and tritium are sometimes represented by the symbols D and T (instead of 2H and 3H), however, the letter P is already reserved for phosphorus and cannot be used for protium. Any of D, T, 2H or 3H can be used in the nomenclatural recommendations issued by the International Union of Pure and Applied Chemistry (IUPAC). 2H and 3H are favored.

Due to the mass difference between the antimuon and the electron, muonium (symbol Mu) is also sometimes referred to as a light hydrogen radioisotope. Discoveries of muonium were made in 1960. Muonium can get into compounds such as MuCl or NaMuO2 during the muon’s 2.2-second lifespan.


In contrast to other elements, each of its isotopes has a different name in general usage today. Only deuterium and tritium have their original isotope names, which were employed in the early days of radioactivity research.

:eight_pointed_black_star: Safety And Precautions For Hydrogen

Safety And Precautions For Hydrogen

In terms of human safety, hydrogen offers a multitude of risks, ranging from the possibility of detonations and fires when mixed with air to the fact that it is an asphyxiant when in its pure, oxygen-free state.

In addition to leaking out, hydrogen can cause harmful effects on the metals themselves. The hydrogen gas that has leaked into the atmosphere has the potential to spontaneously ignite. Furthermore, even though hydrogen fire is incredibly hot, it is nearly imperceptible, and as a result, it might result in inadvertent burns. Even the interpretation of hydrogen data (particularly safety is complicated by a variety of interrelated factors.

The parahydrogen/orthohydrogen ratio has an impact on a variety of physical and chemical characteristics of hydrogen (it often takes days or weeks at a given temperature to reach the equilibrium ratio, for which the data is usually given). The shape of the container has a significant impact on the parameters of hydrogen detonation, such as the critical detonation pressure and temperature.


In addition, because liquid hydrogen is a cryogen, it has the risks (such as frostbite) that come with handling extremely cold liquids. When hydrogen combines with metals, it may have a variety of detrimental consequences, including hydrogen embrittlement, which can result in cracks and explosions.

Frequently Asked Questions - FAQs

People asked many questions about the radius of hydrogen. We discussed a few of them below:

:one: Where does the hydrogen come from?

It may be generated by "decomposing the water molecule to hydrogen and oxygen gas." Because molecular hydrogen is a tasteless and odorless gas, hydrogen water has no distinct flavor or aroma.

:two: How long does hydrogen remain stable in water once it has been dissolved?

For up to eight hours, hydrogen water retains its antioxidant qualities when kept in a hermetically sealed glass bottle without an air chamber.

:three: Is hydrogen toxic to humans?

Hydrogen, it’s true, is dangerous to human health. Inhalation of hydrogen, even in low quantities, can result in symptoms such as headache, nausea, skin and eye irritation, and convulsions. Hydrogen asphyxiation can occur if a large quantity of hydrogen is inhaled.

:four: Which is better alkaline or hydrogen water?

The term “hydrogen water” simply refers to water that has free hydrogen available to function as an antioxidant to scavenge ROS that causes harm. You’ll get both the benefits of alkaline pH and a high dissolved hydrogen content by drinking alkaline ionized water.

:five: Is hydrogen a good source of energy?

Because of its high energy content per unit of weight, hydrogen is valuable as a fuel for rockets and in fuel cells on some spacecraft, which is why it is employed. In the short term, hydrogen is not frequently used as a fuel, although this might change in the future.

:six: What is hydrogen’s orbit?

Because hydrogen only has one electron, it will be positioned in the 1s orbital, which has the lowest energy. The electrical structure of hydrogen is 1s1. This orbital has already been discussed previously.

:seven: Does exist a market for hydrogen water?

In certain cases, hydrogen water is sold in bottles with the gas pre-mixed. Hydrogen water pills are also available for sale. Add the gas by placing one in a glass of water. Health advantages of hydrogen water have yet to be shown, and additional study is needed to verify these findings.

:eight: What is the electron’s velocity about the hydrogen atom’s orbit?

Zn is the hydrogen atom’s atomic number, hence the electron’s velocity in the nth orbit is vn=2.18106zn. The electron’s nth-orbit velocity to the speed of light (v) ratio is 1:411.

:nine: What are the negative effects of drinking water that has been treated with hydrogen?

Fatigue, nausea, diarrhea, dry mouth, lack of appetite, hair loss, painful skin, and depression are just a few of the acute radiation side effects. Cancer, central nervous system diseases, cardiovascular disease, and cataracts are among the long-term consequences of radiation exposure.

:keycap_ten: Where is the radius in a circle?

It is the distance from the center of the circle to any point on its perimeter that is known as the radius of a circular object. ‘R’ or ‘r’ is the most common abbreviation. Almost all calculations involving circles rely on this value. The radius is also used to calculate a circle’s surface area and circumference.

:closed_book: Conclusion

Several bacteria create H2 as a byproduct of anaerobic metabolism, mainly through processes catalyzed by hydrogenases, which contain iron or nickel-containing enzymes. The redox reaction between H2 and its two protons and two electrons is catalyzed by these enzymes.

Microbes in the large intestine that contain hydrogenase are responsible for producing hydrogen in human breath. Diagnostic hydrogen breath tests can detect up to 50 parts per million (ppm) in persons with intestinal issues who ingest molecules they cannot process when fasting, although the concentration is normally less than 5 parts per million (ppm). Methane, an increasingly important hydrogen source, is generated by bacteria and algae and is a naturally occurring component of flatus.

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