Noble gas

Noble gases are special elements found in group 18 of the periodic table. They include helium, neon, argon, krypton, xenon, and radon. These gases are mostly colorless, odorless, and do not react easily with other substances. This is because their outer shell of electrons is full, making them very stable.

Because noble gases do not react easily, they are very useful. For example, argon is used to protect materials during welding and to fill light bulbs. Helium can make things float and is used in balloons and blimps. Both helium and neon can also keep things very cold, so they are used in cooling systems.

Most noble gases are found in the air and can be separated from it. Helium can also come from natural gas. Radon is different because it comes from the decay of certain radioactive materials. The last member of this group is oganesson, a man-made element that is very unstable and does not last long. Its properties are still being studied.

History

The noble gases got their name from the German word Edelgas, which means they don’t react with other elements very easily.

Scientists discovered these gases over many years. In 1868, two astronomers found a new element in the Sun and named it helium. In 1895, two scientists found another gas in the air and named it argon. They realized there was a whole group of gases missing from the table that shows all the elements. They later found three more gases: neon, krypton, and xenon. In 1898, another scientist found radon. These discoveries helped scientists understand how atoms are built. In 2006, scientists created a new element called oganesson in a laboratory.

Physical and atomic properties

For more data, see Noble gas (data page).

Noble gases have low melting and boiling points because their atoms push each other away easily. They are all single atoms under normal conditions, even though some weigh more than materials that are usually solid. Helium is special because it stays liquid even at very cold temperatures unless you press it hard.

Noble gas atoms get bigger as you go down the group because they have more electrons. This size affects how easily they can lose electrons. These gases are very stable and don’t react with much, which is why they are called noble. However, some heavier noble gases can react a little more easily. The weak forces between their atoms mean they behave almost like perfect gases, and these gases helped scientists understand how atoms interact with each other.

Chemical properties

Noble gases are colorless, odorless, tasteless, and do not catch fire under normal conditions. They were once thought to never form compounds because their atoms cannot combine with others. But now we know some noble gases can form compounds.

Like other elements, noble gases have patterns in their electron setup, especially in their outer shells. This affects how they behave. Noble gases have full outer electron shells, making them very stable and unlikely to form bonds with other elements. But heavier noble gases, such as radon, have outer electrons that are easier to remove.

Because of their full electron shells, noble gases help us understand the electron setup of other elements. For example, phosphorus has a complex setup, but we can write it more simply by using the noble gas that comes before it, neon.

Noble gases usually don’t react, but a few hundred compounds have been made. Helium and neon haven’t formed neutral compounds, but xenon, krypton, and argon have shown some ability to react. Scientists predicted that heavier noble gases could form compounds with fluorine and oxygen, and many such compounds have been created, especially with xenon.

Xenon forms the most compounds. These include xenon bonded to fluorine or oxygen. For example, xenon difluoride is used in certain chemical reactions. Radon is more reactive than xenon but is hard to study because it changes quickly. Krypton also forms a few compounds, like krypton difluoride. Scientists have also made a few compounds with argon, but stable compounds with helium or neon are still unknown.

Noble gases can also form other types of compounds, such as ions and clathrates, where the gas is trapped inside other structures. These help scientists study different materials.

Occurrence

Noble gases are found in different amounts in the universe and on Earth. In space, helium is the second most common element after hydrogen. Most helium was made shortly after the Big Bang, and more is still being made inside stars.

On Earth, helium is less common in the air because it is too light to stay near the ground. Instead, Earth’s helium comes from deep inside the planet, where heavy elements break down and release it. Argon is more common on Earth because it is made when a certain type of potassium breaks down. Xenon, another noble gas, is found in smaller amounts in our air than scientists expect, and they think it might be hidden inside rocks. Radon is created deep in the Earth and can sometimes get into buildings. Oganesson is not found in nature; scientists make it in laboratories.

Extraction

Neon, argon, krypton, and xenon come from air. We cool the air to make it a liquid and then heat it up to separate the gases. Helium is usually taken from natural gas, and radon comes from the breakdown of radium compounds. The cost of these gases depends on how much of them exist in nature. Argon is the cheapest, while xenon is the most expensive.

Biological chemistry

None of the elements in this group are important for living things.

Applications

Noble gases have very low boiling and melting points, so they are useful for cooling things down. For example, liquid helium is used in special magnets for certain medical machines. Liquid neon can also be used for very cold temperatures.

Helium helps people breathe safely underwater because it does not cause problems like regular air at deep depths. It is also used to fill balloons and blimps because it does not catch fire, unlike hydrogen. Argon gas is used to stop reactions in some chemical processes.

Noble gases are often used in lights because they do not react with other materials. Argon is used in regular light bulbs, while krypton is used in more efficient bulbs. Neon lights glow in bright colors because of these gases.

These gases are also used in special lasers that can make very precise cuts or help with medical treatments. Some noble gases, like xenon, can be used in medical ways to help people breathe easier or see inside the body better.

Noble gases in Earth sciences application

Scientists study noble gases to learn about Earth’s history. By looking at the different types of these gases, they can figure out how gases have moved and changed over time.

Helium

Helium has two main types, and by studying them, scientists can learn about deep parts of the Earth.

Neon

Neon also has different types that help scientists understand the Earth’s mantle and other deep places.

Argon

Argon has three stable types that help scientists study the Earth’s crust and atmosphere.

Krypton

Krypton’s types help scientists understand how gases came to Earth and how our planet developed.

Xenon

Xenon has nine types, most made by natural processes, and studying them helps scientists avoid contamination and use special tools to analyze them.

Sampling of noble gases

Scientists collect noble gases from places like volcanic vents and springs using special methods and tools to keep the samples clean.

Analysis of noble gases

To study noble gases, scientists use special machines that can detect very small amounts and different types of these gases.