• The elements are;
  • Helium, He
  • Neon, Ne
  • Argon, Ar
  • Krypton, Kr
  • Xenon, Xe
  • Radon, Rn
• Also known as inert gases or noble gases.
• Can be found at the far-right column of the Periodic Table.

Physical properties

• Insoluble in water.
• Does not conduct electricity.
• Does not conduct heat.
• The boiling and melting point is increasing down the group.
• The van der Waals forces are increasing when the size of the atoms increases.

Chemical properties

• Does not react with other elements.
• Exists as a monatomic (single atom). 
• Inert gases are non-reactive because the valence shell is full.
• For example, helium has a stable duplet electron arrangement, because the number of valence electrons is two.
• The other elements in Group 18 have a stable octet electron arrangement because the number of valence electrons is eight.
• Noble gas did not accept or donate electrons as it is already stable.