What Are the Main Properties and Uses of Helium?
Helium is essential in chemistry and helps students understand various practical and theoretical applications related to this topic.
Learning about the properties, uses, and natural occurrence of helium prepares you for fundamental concepts in elements and gases, as well as exciting real-world examples like balloons, cryogenics, and even space research.
What is Helium in Chemistry?
A helium element refers to a noble gas with the chemical symbol He and atomic number 2. This concept appears in chapters related to atomic structure, noble gases, and periodic table trends, making it a foundational part of your chemistry syllabus.
Helium stands out due to its low density, inertness, and unique behavior at extremely low temperatures.
Molecular Formula and Composition
The molecular formula of helium is He. It consists of a single atom per molecule, as helium is a monoatomic noble gas and is categorized under Group 18 elements. Helium’s stable electron configuration (1s2) is at the heart of its chemical inactivity.
Preparation and Synthesis Methods
Helium is not synthesized in laboratory settings in large quantities due to its rarity and because it is not part of any typical chemical reaction. Instead, it is obtained through extraction from natural gas deposits, where it can be as much as 7% of the mixture.
Industrial gas separation processes—mainly fractional distillation and adsorption on cooled activated charcoal—allow the removal of other gases, leaving behind nearly pure helium. In the Earth's crust, helium is produced naturally from the alpha decay of heavy radioactive elements like uranium and thorium.
Physical Properties of Helium
Helium is a colorless, odorless, and tasteless gas at room temperature. It has the lowest boiling point among all elements at -268.9°C and remains liquid even at absolute zero under normal pressure.
Helium is lighter than air (about 1/7th its density), non-flammable, and only slightly soluble in water. It is also non-toxic, with extremely low viscosity and a unique property known as superfluidity at very low temperatures.
Chemical Properties and Reactions
Helium is an inert gas that does not form compounds easily because of its stable, fully-filled electron shell configuration. It does not react with acids, alkalis, or oxygen and is not flammable.
Under very special high-energy conditions, some exotic compounds with other noble gases or ions can be formed, but these are rare and of minimal practical significance.
Frequent Related Errors
- Confusing helium with hydrogen (hydrogen is lighter but flammable, helium is not).
- Assuming helium can react or burn like other gases (helium is chemically inert).
- Thinking helium is abundant in Earth’s air; in reality, it’s rare on Earth and mainly extracted from natural gas, not from the air directly.
Uses of Helium in Real Life
Helium is widely used in real life. Its most popular use is in filling party and weather balloons because it is lighter than air and safe (not flammable). In medicine, liquid helium is crucial for cooling MRI scanners and superconducting magnets due to its extremely low temperature.
Helium is used as a protective, inert atmosphere in arc welding, as a pressurizing agent in rocket fuel tanks, and as a safe breathing gas for deep-sea divers. Helium also finds importance in scientific research for producing super-cold conditions in physics experiments.
Relation with Other Chemistry Concepts
Helium is closely related to topics such as noble gases and atomic structure, helping students build a conceptual bridge between periodic trends and the reason behind chemical inertness. Understanding helium’s full electron shell demonstrates the basis for low reactivity seen in other Group 18 elements, too.
Step-by-Step Reaction Example
- Extraction of helium from natural gas:
Natural gas (containing helium) is cooled and pressurized to remove methane and other impurities by liquefaction. Helium remains as the last gas. - Further purification:
The remaining gases are removed by adsorption on activated charcoal at very low temperatures, isolating 99.99% pure helium.
Lab or Experimental Tips
Remember helium by its lightness and non-reactive nature. If you ever see a balloon that doesn’t burn when exposed to a flame, it’s likely filled with helium. Vedantu educators often mention helium’s use in MRI machines and cutting-edge lab experiments as a fun way to link everyday life with science.
Try This Yourself
- Write the electron configuration of helium and explain why it is inert.
- Name two differences between helium and hydrogen gases.
- List three real-life uses of helium that are important for health or science.
Final Wrap-Up
We explored helium—its structure, unique properties, real-world applications, and its inert behavior. For more in-depth explanations, live classes, and study notes on periodic trends and cool chemistry facts, check Vedantu’s chemistry modules. Understanding helium is not just key for exams, but also for discovering the wonders of science and technology.
Further Reading: Periodic Table
FAQs on Helium – Properties, Applications, and Conservation
1. What is helium and where is it found?
Helium is a colorless, odorless, inert gas that is the second element on the periodic table.
Occurrence:
- Found mostly in natural gas deposits underground
- Present in stars and the sun
- Traces of helium are found in the Earth’s atmosphere
2. Why is helium considered a noble gas?
Helium is a noble gas because:
- It has a completely filled outermost electron shell (1s2)
- It is chemically inert and rarely reacts with other elements
- Belongs to Group 18 of the periodic table along with other noble gases like neon and argon
3. What are the main uses of helium?
Helium is used in many important ways:
- Filling party balloons and scientific blimps
- As a coolant in MRI machines (cryogenics)
- Protective gas for arc welding
- Used in space technology and scientific research
- Creating controlled atmospheres for sensitive equipment
4. What is the atomic number and symbol of helium?
Helium has the chemical symbol He and an atomic number of 2. It is located in Group 18 (noble gases) of the periodic table.
5. Why is helium chemically unreactive?
Helium is chemically unreactive because:
- It has a complete valence electron shell (1s2)
- There is no tendency to gain, lose, or share electrons
- This makes it the most inert element in chemistry
6. How is helium obtained from natural sources?
Helium is primarily extracted from natural gas deposits that contain high concentrations of helium.
Steps include:
- Drilling and collecting natural gas
- Separating helium using low-temperature distillation
- Purifying and compressing the helium gas for various uses
7. What are some interesting facts about helium?
Here are some fun and useful facts:
- Second most abundant element in the universe
- Does not solidify at atmospheric pressure due to its low boiling point
- Changes your voice to a higher pitch if inhaled (not safe)
- Essential for cooling superconducting magnets (like MRI)
- First discovered in the sun’s spectrum, not on Earth
8. What will happen if we run out of helium?
Running out of helium can cause:
- Shortages in medical imaging (MRI machines)
- Problems in scientific research and cryogenics
- Loss of uses in space exploration and industrial applications
- Higher prices and possibly restricted access to helium-filled products
9. Can we extract helium directly from the air?
Extracting helium from air is technically possible, but:
- Helium makes up only 0.0005% of Earth’s atmosphere
- It is not economical compared to extraction from natural gas reserves
- Most commercial helium comes from underground sources, not air
10. What are helium isotopes and why are they important?
Helium has two main stable isotopes:
- Helium-4: Most common, used in balloons and cooling
- Helium-3: Rare, important for nuclear research and quantum science
- Isotopes affect helium’s behavior in physics and fusion studies
11. Is inhaling helium gas dangerous?
Inhaling helium is unsafe and should be avoided.
Risks include:
- Displacing oxygen in the lungs
- Possible suffocation and unconsciousness
- Should never be used for fun or voice changes
12. Why is helium used instead of hydrogen in balloons?
Helium is preferred over hydrogen in balloons because:
- It is lighter than air and makes balloons float
- Non-flammable and much safer than explosive hydrogen
- Does not react with other elements, reducing risks
