Okay, helium balloons room light...but they"re no that light! The fanciful image below serves to do the allude that helium is one of the lightest elements. Helium belongs come a team of facets called the noble gases.

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Figure \(\PageIndex1\): Helium is one of the lightest aspects in the periodic table.

What space Noble Gases?

Noble gases space nonreactive, nonmetallic elements in team 18 the the regular table. As you have the right to see in the routine table in the number below, noble gases encompass helium \(\left( \ceHe \right)\), neon \(\left( \ceNe \right)\), argon \(\left( \ceAr \right)\), krypton \(\left( \ceKr \right)\), xenon \(\left( \ceXe \right)\), and also radon \(\left( \ceRn \right)\). All noble gases room colorless and odorless. They also have short boiling points, which describes why they are all gases at room temperature. Radon, at the bottom of the group, is radioactive, so that constantly decays to other elements.

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Figure \(\PageIndex2\): Noble gases room in team 18 that the routine table, in this case the red pillar on the much right.

stayinfiji.comical nature of Noble Gases

Noble gases space the least reactive of all recognized elements. Their outer energy levels room full due to the fact that they each have actually eight valence electrons. The only exemption is helium, which has actually just two electrons. However helium additionally has a complete outer power level, because its only power level (energy level 1) can hold a preferably of 2 electrons. A complete outer power level is the most stable plan of electrons. As a result, noble gases cannot become an ext stable by reacting with other elements and also gaining or losing valence electrons. Therefore, noble gases are rarely connected in stayinfiji.comical reaction and practically never form compounds with other elements.


Noble Gases and also the Octet Rule

Because the noble gases room the least reactive of every elements, their eight valence electron are provided as the typical for non-reactivity, and also to describe how other facets interact. This is proclaimed as the octet ("group the eight") rule. Follow to this rule, atoms react to form compounds that enable them to have a team of eight valence electrons like the noble gases. Because that example, salt (with one valence electron) reacts v chlorine (with 7 valence electrons) to form the stable compound salt chloride (table salt). In this reaction, sodium donates one electron and chlorine accepts it, providing each facet an octet that valence electrons.


Some uses of Noble Gases

Have you ever hadhelium balloons choose those in the elephant image? uneven a balloon filled through air, a balloon filled v helium needs to be weighted under so the it won"t float away—although friend don"t have to use an elephant!

Early incandescent light bulbs, choose the one pictured in the figure below, didn"t last an extremely long. The filaments quickly burned out. Back air to be pumped out of the bulb, the wasn"t a finish vacuum. Oxygen in the small amount of air remaining inside the light pear reacted through the metal filament. This corroded the filament and also caused dark deposits on the glass. Pour it until it is full a irradiate bulb v argon gas stays clear of these problems. That"s why modern-day light bulbs space filled with argon.

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Figure \(\PageIndex3\): modern light bulbs room filled v the noble gas argon to prevent corrosion the the filament inside.

Noble gases are additionally used to fill the glass tube of lighted signs like the one in the figure below. Although noble gases room stayinfiji.comically nonreactive, their electrons can be energized by sending an electric existing through them. Once this happens, the electrons jump to a greater energy level. Once the electrons go back to their original energy level, they give off energy as light. Various noble gases offer off light of different colors. Neon gives off a reddish-orange light, like the indigenous "Open" in the sign below. Krypton provides off violet light and xenon provides off blue light.

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Figure \(\PageIndex4\): signs like this one room filled through nobles gases prefer neon or xenon, which offer off light as soon as energized.