Properties of Noble Gases

Noble Gases :- All the elements of the 18th group of periodic table are known as Noble Gases . The 18th group consists of six gaseous elements namely - Helium (He) , Neon (Ne) , Argon (Ar) , Krypton (Kr) , Xenon (XE) and Radon (Rn) . Radon is the only radioactive element of the group . They have completely filled outermost orbital (valence shell) . They are also known as Zero Group Elements .

Properties of Noble Gases :

1. Boiling Points and Melting Points - Noble gases possess very low melting point (M.P.) and boiling point (B.P.) because they have very weak Van der Waals forces between their molecules . But the M.P. and B.P. increases on increase in atomic mass i.e. on going downwards in group .

2. Ionisation Enthalpy - Since the outermost shell of Noble Gases are completely filled , hence they possess much higher ionisation enthalpy than other elements . Ionisation enthalpy decreases as we move down in the group .

3. Electron Affinity - As because Noble gases have a completely filled outermost orbital , their electron affinity values are almost zero. They show no tendency to acquire a single electron .

4. Atomic Radius - Atomic radius of noble gases increases on moving down the group because of the addition of a new energy level on stepping down .

5. Monoatomic Nature - Noble Gases do not loose or gain electrons as we discussed above about their completely filled outermost shell , they exist as single atoms i.e. they are monoatomic gases .

6. State - All the Noble Gases are colourless , odourless and tasteless gases .

7. Adsorption - Except helium , all the noble gases are adsorbed by charcoal where their degree of adsorption increases with atomic mass.

8. Solubility - Noble gases are soluble in water . Solubility of noble gases increased with increase in atomic mass . The reason of their solubility in water is dipole-induced dipole interaction .

9. Noble gases are fairly conductors of electricity .

These are some general physical properties of Noble Gases . Hope it will be helpful to you.

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