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Helium can be defined as a chemical element with the symbol He and its atomic number is 2. It is a colourless, tasteless, non-toxic, inert, monatomic gas and therefore the first among the noble gases in the periodic table. Its boiling point, as well as the melting point, are the lowest when compared to all the elements. It is the second lightest and the second most abundant element within the observable universe. The first evidence of helium was observed on August 18th, 1868, as a bright yellow line with a wavelength of 587.49 nanometers in the spectrum of the chromosphere of the Sun.
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Key Terms: Helium, Elements, Isotopes, Boiling Point, Melting Point, Noble Gas, Thermal Conductivity, Spectrum, Atomic Number
What is Helium?
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Helium is the lightest noble gas and was discovered by Pierre Janssen, a French astronomer who also detected a bright yellow line in the solar chromosphere spectrum in 1868. The word Helium is derived from the Greek word ‘Helios’ which translates as the sun.
- It is a chemical element with the symbol He.
- The atomic number of Helium is 2 which comes first among the noble gasses in the periodic table.
- Helium’s outermost electron orbit is filled with two electrons due to which it falls under inert gas.
- Its boiling point and melting point are the lowest amongst all other elements.
- Nuclear fusion of hydrogen in stars leads to the production of a large amount of helium.
- Helium can also be traced in lasers, compressed air tanks and coolants in nuclear reactors.
- Helium is the only element in the periodic table that cannot be solidified by sufficient cooling at normal atmospheric pressure.
Helium
Read More:
| Related Links | ||
|---|---|---|
| Transuranium Elements | Group 18 Elements | Transition Metals |
| The d-block Elements | Ruthenium | Isotopes of Hydrogen |
| Atomic And Molecular Masses | The P-Block Elements | Boron Family |
Isotopes of Helium
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The nucleus of every helium atom contains two protons, isotopes of helium exist. Although there are eight isotopes of helium, only helium-3 (3He) and Helium-4 (4He) are stable, all others are radioactive, decaying very rapidly into other substances. The helium that is available on Earth is not a primordial component but has been formed by radioactive decay.
Properties of Helium
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Helium is an odourless, tasteless, colourless, non-toxic and inert gas. The viscosity and density of helium are very low. Helium-4 is unique in having 2 liquid forms, one of which exists at temperatures from its boiling point of 4.21K down to about 2.18K. With the boiling point below 2.18K, the thermal conductivity of helium-4 becomes over 1000 times greater than that of copper. Physical Properties of Helium The physical properties of Helium are tabulated as follows:
| Helium (He) | Physical Properties |
|---|---|
| Melting Point | 0.95 K (or -272.2°C) |
| Boiling Point | 4.222 K (or -268.928°C) |
| Density | 0.1786 g/L at STP 0.145 g.cm-3 at its melting point |
| Critical Temperature and Pressure | 5.195 K; 0.227 MPa |
| Triple Point | 2.177 K; 5.043 kPa |
| Appearance (at STP) | Colorless gas |
Chemical Properties of Helium
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The chemical properties of Helium are tabulated below:
| Helium (He) | Chemical Properties |
|---|---|
| Electron Configuration | 1s2 |
| First Ionization Energy | 2372.3 kilojoules per mole |
| Second Ionization Energy | 5250.5 kilojoules per mole |
| Van der Waals Radius | 140 picometers |
| Enthalpy of Fusion | 0.0138 kilojoules/mole |
Uses of Helium
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Some major uses of Helium are as follows:
- Helium is used in the formation of germanium crystals as well as silicon crystals.
- It finds its use as a carrier gas in gas chromatography.
- It is used as an inert gas atmosphere for welding of metals such as aluminium.
- It is used in high-pressure breathing operations alongside oxygen, due to its low solubility in the bloodstream.
- Helium is utilised in altitude research and meteorological balloons.
- Liquid helium has various applications in cryogenics, magnetic resonance imaging and superconducting magnets due to its low melting point.
- Helium is used in industries for pipeline leak detection owing to its ability to diffuse through solids much faster than air.
- It is also often used in decorative balloons, weather balloons and airships.
Helium Balloons
Health Effects of Helium
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The health effects of Helium are discussed below:
- Excessive inhalation of helium can cause dizziness, nausea, vomiting, loss of consciousness and headache.
- Very high levels of helium can cause death due to suffocation from lack of oxygen.
- Contact with liquid helium can lead to frostbite.
- Death may arise from confusion, errors in judgement, or loss of consciousness that avoids self-rescue.
Things to Remember
- Helium makes up around 24% of the mass of the universe and it is the second most abundant element.
- Helium is symbolized by He and its atomic number is 2.
- Its boiling point and its melting points are the lowest compared to all the elements.
- Helium-3 and helium-4 are the only two stable isotopes of Helium.
- It is a colourless, odourless, tasteless, inert gas with very low density and viscosity. Helium is so light that it can escape Earth’s gravity.
- Certain uses of helium are altitude research and meteorological balloons; decorative and weather balloons; chromatography; industrial pipeline leak detection, etc.
- Extreme inhalation of helium can cause dizziness, nausea, vomiting, headache, frostbite as well as death.
Also Read:
Previous Year Questions
- Identify the wrong statement in the following.[ NEET 2012 ]
- The most dangerous reaction of an acid is with the metal: [ JIPMER 2000 ]
- Which of the following among alkali metal is most reactive? [BITSAT 2014]
- The correct order of the mobility of the alkali metal ions in aqueous solution is… [NEET 2006]
- Bleaching powder is obtained by the action of chlorine gas and… [NEET 1988]
- Ionic mobility of which of the following alkali metal ions is lowest when aqueous solution of their salts are put under an electric field ? [NEET 2017]
- Which one of the following is present as an active ingredient in bleaching powder for bleaching action? [NEET 2011]
- Aluminium reacts with caustic soda to form: [MU OET 2005]
Sample Questions
Ques. What type of element is helium? (3 Marks)
Ans. Helium is a colourless, tasteless, odourless and inert gas. It is the second lightest element. It is liquid at −268.9°C. Helium has very low boiling and melting points as well as low density and viscosity. Helium is the only element in the modern periodic table to date that has been discovered by an astronomer.
Ques. Who discovered helium? Where is helium found? (3 Marks)
Ans. Helium is the lightest noble gas and was discovered by Pierre Janssen, a French astronomer who also detected a bright yellow line in the solar chromosphere spectrum in 1868 with a wavelength of 587.49 nanometers. Helium is found in the sun and Jupiter. Helium-4 is referred to as the most common form of Helium. Helium is relatively rare on earth, the one that is available on Earth is not a primordial component but has been formed by radioactive decay.
Ques. Where is helium produced today? How is helium made? (3 Marks)
Ans. Helium can only be found in certain gas fields around the world. The major sources exist in the US, Qatar and Algeria, whereas the smaller sources can be found in Australia, Russia and Poland. New helium cannot be produced in a lab as it is a nonrenewable resource and forms very slowly over time via alpha decay in rocks. It begins as a different heavier element, when exposed to radioactive elements, it begins to decay which means that it splits, forming two lighter smaller atoms, one of which is helium.
Ques. What are the uses of Helium? (3 Marks)
Ans. Helium is used in the formation of germanium crystals as well as silicon crystals. It is also used in gas chromatography as a carrier gas. Helium acts as an inert gas atmosphere for welding metals. It is also used in high-pressure breathing operations alongside oxygen. Helium is utilised in altitude research and meteorological balloons. Helium is used in industries for pipeline leak detection.
Ques. What are the health hazards of Helium? (3 Marks)
Ans. Inhaling helium in excess can lead to dizziness, nausea, headache, lightheadedness, and vomiting. Extreme levels of helium can cause death due to suffocation from lack of oxygen. When the skin comes in contact with liquid helium it can cause frostbites. Helium can also enter the lungs with enough force to cause the lungs to rupture.
Ques. Can we survive without Helium? (3 Marks)
Ans. People would live a completely different life without Helium. We have to use it as little as we can. Rockets might not work. Airships would have to be filled with hydrogen instead which can easily catch fire and be much more hazardous. Helium is very useful as it doesn’t catch fire easily. It is even lighter than air.
Ques. Which country produces the most helium? Who is the largest consumer of Helium? (3 Marks)
Ans. The United States was the largest producer of helium in 2019, which generated about 68 million cubic meters. Next comes Qatar which produced 51 million cubic meters in the same year. Third, came Algeria which produced about 14 million cubic meters of Helium. The biggest consumer of helium is NASA, consuming almost 75 million cubic feet of helium annually. The second biggest consumer is the USA Department of Defense, which uses a major quantity to cool liquid hydrogen and oxygen for rocket fuel.
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