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Noble gas

Noble gas is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Noble gas rather than just read about it. In short: The noble gases (historically the inert gases, sometimes referred to as aerogens) are the members of group 18 of the periodic table: helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), radon (Rn) and, in some cases, oganesson (Og). Under standard conditions, the first six of these elements are odorless, colorless, monatomic gases with very low chemical reactivity and cryogenic boiling points.

Noble gas — main illustration
Noble gas — illustration

Key takeaways

  • Noble gas belongs to science; place it in that map before memorising details.
  • Learn the definition first, then one example that makes the definition concrete.
  • Connect Noble gas to a quantity you can measure, compute or draw — that is where exam questions come from.
  • Reproduce the core statement of Noble gas from memory before moving on to harder problems.

Reference excerpt

The noble gases (historically the inert gases, sometimes referred to as aerogens) are the members of group 18 of the periodic table: helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), radon (Rn) and, in some cases, oganesson (Og). Under standard conditions, the first six of these elements are odorless, colorless, monatomic gases with very low chemical reactivity and cryogenic boiling points. The properties of oganesson are uncertain. The intermolecular force between noble gas atoms is the very weak London dispersion force, so their boiling points are all cryogenic, below 165 K (−108 °C; −163 °F). The noble gases' inertness, or tendency not to react with other chemical substances, results from their electron configuration: their outer shell of valence electrons is "full", giving them little tendency to participate in chemical reactions. Only a few hundred noble gas compounds are known to exist. The inertness of noble gases makes them useful whenever chemical reactions are unwanted. For example, argon is used as a shielding gas in welding and as a filler gas in incandescent light bulbs. Helium is used to provide buoyancy in blimps and balloons. Helium and neon are also used as refrigerants due to their low boiling points. Industrial quantities of the noble gases, except for radon, are obtained by separating them from air using the methods of liquefaction of gases and fractional distillation. Helium is also a byproduct of the mining of natural gas. Radon is usually isolated from the radioactive decay of dissolved radium, thorium, or uranium compounds. The seventh member of group 18 is oganesson, an unstable synthetic element whose chemistry is still uncertain because only five very short-lived atoms (t1/2 = 0.69 ms) have ever been synthesized (as of 2020). IUPAC uses the term "noble gas" interchangeably with "group 18" and thus includes oganesson; however, due to relativistic effects, oganesson is predicted to be a solid under standard conditions and reactive enough not to qualify functionally as "noble".

History Noble gas is translated from the German noun Edelgas, first used in 1900 by Hugo Erdmann to indicate their extremely low level of reactivity. The name makes an analogy to the term "noble metals", which also have low reactivity. The noble gases have also been referred to as inert gases, but this label is deprecated as many noble gas compounds are now known. Rare gases is another term that was used, but this is also inaccurate because argon forms a fairly considerable part (0.94% by volume, 1.3% by mass) of the Earth's atmosphere due to decay of radioactive potassium-40.

… excerpt ends here. Continue reading the full article.

Illustrations

Noble gas: This is a plot of ionization potential versus atomic number. The noble gases have the largest ionization potential for each period, although period 7 is expected to break this trend because the predicted first ionization energy of oganesson (Z = 118) is lower than those of elements 110–112.
This is a plot of ionization potential versus atomic number. The noble gases have the largest ionization potential for each period, although period 7 is expected to break this trend because the predicted first ionization energy of oganesson (Z = 118) is lower than those of elements 110–112.
Noble gas: Neon, like all noble gases, has a full valence shell. Noble gases have eight electrons in their outermost shell, except in the case of helium, which has two.
Neon, like all noble gases, has a full valence shell. Noble gases have eight electrons in their outermost shell, except in the case of helium, which has two.
Noble gas: Structure of xenon tetrafluoride (XeF4), one of the first noble gas compounds to be discovered
Structure of xenon tetrafluoride (XeF4), one of the first noble gas compounds to be discovered
Noble gas: An endohedral fullerene compound containing a noble gas atom
An endohedral fullerene compound containing a noble gas atom
Noble gas: Bonding in XeF2 according to the 3-center-4-electron bond model
Bonding in XeF2 according to the 3-center-4-electron bond model

Worked examples

Example 1 — a first encounter with Noble gas

Start with the simplest possible case. Write down what Noble gas claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Noble gas before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Noble gas ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Noble gas

In research
Noble gas appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry
Engineering practice reuses Noble gas in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom
Noble gas is common in secondary-school and first-year university syllabi. It links to neighbouring topics Groups (periodic table), Noble gases, so understanding it makes those chapters shorter.
In everyday life
Look for Noble gas outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.
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How to study Noble gas in 20 minutes

  1. Read the reference excerpt below once, without taking notes.
  2. Close the page and write down what Noble gas means in your own words.
  3. Compare your version with the excerpt and mark what you missed.
  4. Work through the three examples above with pen and paper.
  5. Explain Noble gas out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Noble gas in simple terms?

The noble gases (historically the inert gases, sometimes referred to as aerogens) are the members of group 18 of the periodic table: helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), radon (Rn) and, in some cases, oganesson (Og). Under standard conditions, the first six of these element…

Why does Noble gas matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Noble gas?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Noble gas.

Tags

  • Groups (periodic table)
  • Noble gases

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