Question

Give reason for the following

Valency of noble gases is zero.

Answer 1

• Valency- Valency is the combining capacity of an atom.
• Valence electrons- The electrons present in the valence shell i.e., the outermost shell of an atom are known as valence electrons.
• Valence electrons take part in the chemical reaction.
• These electrons decide the chemical properties of an atom.
• Noble gases have octet or duet configurations.

Octet configuration-

• In a chemical reaction, atoms either donate, accept or share one or more electrons until there are 8 electrons in the outermost shell.
• There are elements that already have 8 electrons in the outermost shell.
• These elements are said to possess octet configuration.
• Elements with octet configuration are said to be stable.
• All noble gases of group 18 in the period table have octet configuration except helium.
• Helium has 2 electrons only in its L shell, and this configuration is known as the duet configuration.
• All noble gases have completely filled the valence shell.
• Hence, their valency is zero.