Why noble gases are unreactive

Which of the following has smallest size? Chemistry Most Viewed Questions. Identify a molecule which does not exist. Identify the incorrect match. Which of the following set of molecules will have zero dipole moment? On electrolysis of dil. An element has a body centered cubic bcc structure with a cell edge of pm. Helium is:. Argon is used as a 'shield gas' when welding pieces of metal together. Argon is:.

Filament lamps contain thin metal wires. These become very hot and glow brightly when an electric current is passed through them. Explain why argon, krypton or xenon are used in these lamps. The hot metal wires will burn away if any oxygen from air is present in the lamp.

Argon, krypton and xenon are very unreactive. According to this rule, atoms react to form compounds that allow them to have a group of eight valence electrons like the noble gases. For example, sodium with one valence electron reacts with chlorine with seven valence electrons to form the stable compound sodium chloride table salt.

In this reaction, sodium donates an electron and chlorine accepts it, giving each element an octet of valence electrons. Have you ever had helium balloons like those in the elephant image? Unlike a balloon filled with air, a balloon filled with helium needs to be weighted down so that it won't float away—although you don't have to use an elephant!

Early incandescent light bulbs, like the one pictured in the figure below, didn't last very long. The filaments quickly burned out.

Although air was pumped out of the bulb, it wasn't a complete vacuum. Oxygen in the small amount of air remaining inside the light bulb reacted with the metal filament.

This corroded the filament and caused dark deposits on the glass. Filling a light bulb with argon gas prevents these problems. That's why modern light bulbs are filled with argon. Noble gases are also used to fill the glass tubes of lighted signs like the one in the figure below. Although noble gases are chemically nonreactive, their electrons can be energized by sending an electric current through them.

When this happens, the electrons jump to a higher energy level. When the electrons return to their original energy level, they give off energy as light.