Noble Gases Notes | Element of Group 18 by MM | Chemical and Physical Property of Noble Gases

                                                                             

                                            NOBLE GASES

         

Introduction  of Noble Gases

                                                                    These gases are also known as Inert Gases or rare gases or nobel    gases . They were called inert gases because they are chemically inert.they occur in nature in less quantities hence were called rare gases. We are also called noble gases because like noble metals they found in free state and enter into some chemical reaction under specific codition 

.

Electronic configuration of noble gases

                                                                            The outer most shell of these  elements has ns², np⁶ electronic configuration except helium because helium has 1s² electronic configuration . the outer most shell of noble gases is full fill so they can neither donate nor accept any electron and that’s why zero- valent they are chemically inert.

          

Atomic  number	Element	Electronic configuration
2	He	1s2
10	Ne	1s2, 2s2, 2p6
18	Ar	1s2, 2s2, 2p6, 3s2, 3p6
36	Kr	1s2, 2s2, 2p6, 3s2, 3p6, 3d10, 4s2, 4p6
54	Xe	1s2, 2s2, 2p6, 3s2, 3p6, 3d10, 4s2, 4p6, 4d10, 5s2, 5p6
86	Rn	1s2, 2s2,2p6, 3s2,3p6,3d10, 4s2, 4p6,4d10, 4f14, 5s2, 5p6, 5d10,  6s2, 6p6

Inertness causes of Noble Gases

·        Noble gases have ns², np⁶ electronic configuration in their outer most shell except helium because it’s have 1s²  electronic configuration. Thus they can neither donate nor accept any electron hence they are chemically inert.

·        All electrons are paired hence electrons are not available for sharing .therefore they are unable to form covalent compounds.

·        Noble gses are unable to expand their valency shell. Thus the formation of compounds  is not possible.

·        Due to low electron affinity they can not accept electrons and hence are unable to form compounds.

Physical properties of noble gases-

·        Noble gases are colourless, odourless, and tasteless.

·        Noble gases are monoatomoc.

·        They are slighty soluble in water.

·        Noble gases can be liquefiedat suitable temperatures.

·        Their atomic radii, density,  melting point, boiling points increase with increase in atomic number.

·        Their ionisation potential gradually decreases at the atomic number increases.

Chemical properties of noble gases-

Noble gases have high ionisation potential and negligible electron affinity,therefor they can neither donate nor accept electrons   they are chemically inert in the normal state.

ü However the noble gases may form compounds under the following conditions .

1.     Compounds formed under excited condition.

2.     Compounds formed through co-ordination.

3.     Compounds formed through dipole induced dipole attraction.

4.     Compounds formed by physical trapping.

Compounds  of xenon- XeF₂  ,  XeF₄ , XeF₆ , XeOF₂ , XeOF₄ , XeO₂F₂ , XeO₃ , XeO₄

Compounds of krypton-  KrF₂ , KrF₄

Compounds of radon-  RaF₄