Noble gases

Introduction

The noble gases are a group of elements located in group 18 (or group 0) of the periodic table. They include helium ( He ), neon ( Ne ), argon ( Ar ), krypton ( Kr ), xenon ( Xe ), and radon ( Rn ). These elements are known for their low reactivity compared to most other elements. This unique property makes them fascinating to study.

Properties of noble gases

The noble gases have several key properties in common:

• Non-reactive: Noble gases are generally not reactive. This means they do not easily form compounds with other elements. Their outer electron shell is filled, which makes them chemically stable.
• Colourless and odourless: All these gases are colourless and have no odour. Hence, they are difficult to detect without special equipment.
• Low boiling point: Noble gases have very low boiling points. For example, helium boils at -268.93°C (-452.07°F), which is very close to absolute zero.
• Low density: They have low density compared to other elements. For example, helium is lighter than air.

Where are noble gases found?

The noble gases make up a small portion of the Earth's atmosphere. Here's an example:

The smaller yellow circle inside the blue circle represents the noble gases present in Earth's atmosphere. Most of the blue region is made up of other gases such as nitrogen and oxygen.

Uses of noble gases

Noble gases have many applications due to their unique properties. Here are some examples:

• Helium: It is used in balloons because it is lighter than air and non-flammable.
• Neon: Used in neon signs for bright, colorful lighting.
• Argon: Commonly used in light bulbs to keep the filament from burning out.

Why are they called "noble" gases?

The term "noble" is related to the term "nobility," which historically has referred to a class above ordinary citizens. Similarly, noble gases are distinct from common elements because they do not react easily with other substances. This non-reactive property is similar to how the nobility in history remained aloof and somewhat insulated from issues faced by the general public.

Stability of noble gases

The most important reason for the stability of noble gases is their electron configuration. Let us understand this with an example:

Helium: 1s 2
Neon: 1s 2 2s 2 2p 6
        

In helium, a single energy level is filled with two electrons. For neon, the outer shell has eight electrons, making it complete and stable.

How were the noble gases discovered?

Helium was discovered in the sun before it was found on Earth. Scientists observed a new spectral line in sunlight during a solar eclipse and named it after the Greek word for the sun, "helios." Argon was discovered by Sir William Ramsay and Lord Rayleigh in the late 1800s. Other noble gases were soon discovered through air analysis.

The discovery of the noble gases was important because it added a new group to the periodic table and helped develop our understanding of atomic theory.

Visualization of noble gases

In the periodic table, the noble gases are found in the last column. They are often represented like this:

The colored blocks represent the noble gases in the periodic table. They always appear in the last column, which shows how they differ from other elements in terms of reactivity.

Conclusion

Understanding the noble gases helps us understand how the elements behave and interact. Despite their lack of chemical reactivity, the noble gases have a variety of practical applications in everyday life and scientific research. From making birthday balloons fly to making city neon lights shine, these seemingly invisible elements play a visible role in the world around us.

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