Okay, helium balloons are light...but they"re no that light! The fanciful image below serves to make the point that helium is just one of the lightest elements. Helium belongs come a team of aspects called the noble gases.

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

What room Noble Gases?

Noble gases space nonreactive, nonmetallic aspects in team 18 the the regular table. As you can see in the routine table in the figure 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 radon \(\left( \ceRn \right)\). Every noble gases space colorless and odorless. They likewise have short boiling points, which explains why they room all gases in ~ room temperature. Radon, at the bottom the the group, is radioactive, so it constantly decays to other elements.

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Figure \(\PageIndex2\): Noble gases room in group 18 of the periodic table, in this instance the red pillar on the much right.

positiveeast.orgical nature of Noble Gases

Noble gases are the the very least reactive of all well-known elements. Your outer power levels room full due to the fact that they each have eight valence electrons. The only exemption is helium, which has just two electrons. However helium likewise has a full outer power level, due to the fact that its only energy level (energy level 1) deserve to hold a maximum of 2 electrons. A full outer energy level is the most stable plan of electrons. As a result, noble gases cannot become an ext stable by reacting with various other elements and also gaining or losing valence electrons. Therefore, noble gases room rarely associated in positiveeast.orgical reaction and nearly never kind compounds with other elements.


Noble Gases and also the Octet Rule

Because the noble gases room the least reactive of all elements, their eight valence electron are used as the standard for non-reactivity, and also to explain how other elements interact. This is proclaimed as the octet ("group of eight") rule. According to this rule, atoms reaction to form compounds that allow them to have actually a group of eight valence electrons favor the noble gases. For example, sodium (with one valence electron) reacts through chlorine (with seven valence electrons) to kind the secure compound salt chloride (table salt). In this reaction, sodium donates one electron and also chlorine accepts it, giving each element an octet that valence electrons.


Some provides of Noble Gases

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

Early incandescent irradiate bulbs, choose the one pictured in the number below, didn"t last really long. The filaments quickly shed out. Return air to be pumped out of the bulb, it wasn"t a finish vacuum. Oxygen in the small amount that air staying inside the light pear reacted through the metal filament. This corroded the filament and also caused dark shop on the glass. Pour it until it is full a irradiate bulb v argon gas prevents these problems. That"s why modern light bulbs room filled with argon.

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Figure \(\PageIndex3\): contemporary light bulbs are filled v the noble gas argon to stop corrosion the the filament inside.

Noble gases are additionally used to to fill the glass pipe of lighted signs like the one in the number below. Return noble gases room positiveeast.orgically nonreactive, their electrons have the right to be energized by sending out an electric present through them. When this happens, the electrons jump to a higher energy level. As soon as the electrons go back to their original energy level, they give off power as light. Various noble gases offer off light of different colors. Neon provides off a reddish-orange light, prefer the indigenous "Open" in the authorize below. Krypton offers off violet light and xenon provides off blue light.

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Figure \(\PageIndex4\): indications like this one space filled with nobles gases favor neon or xenon, which give off light as soon as energized.