Elements of p-Block III Class 12th Notes


Elements of p-Block III Class 12th Notes-Easy Ncert class 12 Elements of p-Block III Class 12th Notes CBSE p block elements…

He, Ne, Ar, Kr, Xe and Rn are the elements of group 18. These are chemically nonreactive so, these are termed as noble gases. All the noble gases except radon occur in the atmosphere while radon is obtained  as a decay product of radium (266Ra).

Isolation of Nobel Gases

  • The main source of inert gases is monozite, which is a radioactive mineral. Helium and radon can also the obtained by radioactive disintegration.

_{ 88 }^{ 266 }{ Ra }\longrightarrow _{ 86 }^{ 88 }{ Rn } + _{ 2 }^{ 4 }{ He }

  • When the mixture of neon and Helium comes in contact with charcoal at 93 K, neon gets completely absorbed. Helium gets free but doesn’t gets absorbed.
  • Separation of noble gas in air is done by Fischer and Ringe’s method.

Electronic configuration- General valence shell electronic configuration of all noble gases is ns2np6 except He which has 1s2 configuration. Due to stable electronic configuration, these gases exhibits very high ionisation enthalphy.

Characteristics and Physical Properties

  • They have high ionization potential because electronic configuration of noble gases is stable and fully filled.
  • They are slightly soluble in water.
  • They all are colourless, odourless and monoatomic gases.
  • The radius of noble gases are van der waal’s radius which are greater than covalent radius.
  • There electron gain enthalpy value is more positive.

Uses of Nobel Gases

  • Due to low solubility in blood the mixture of helium and oxygen is used in breathing by diver.
  • Helium is used in nuclear reactors.
  • Helium is used in balloons.
  • Neon is used in fogging lamps.
  • Argon is used in light bulbs.
  • Radon is used in chemotherapy.
  • Argon is used to create in our atmosphere during metallic arching.


Xenon has least ionisation enthalpy except radon which is radioactive among noble gases, therefore it forms compounds with oxygen and chlorine readily which are the most electronegative element. Xenon makes three binary fluorides,  XeF2 , XeF4, and XeF6. Hydrolysis of XeF4 and XeF6 gives XeO3. Partial hydrolysis of XeF6 gives XeOF4, and XeO2F2.

Elements of p-Block III

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