Question
Question: Valency is the number of electrons accepted by noble gas. (A) True (B) False...
Valency is the number of electrons accepted by noble gas.
(A) True
(B) False
Solution
Hint Valency of oxygen, fluorine, and nitrogen atom is two, one, and three. Atoms of noble are held together by weak van der Waals forces and they do not form molecules. They have very high ionisation enthalpy.
Complete answer:
Valency is the number of electron loss and gain by an atom during the formation of bonds with other atoms. It is defined as the combining capacity of the electrons. In the old concept, valency of an atom is determined with respect to hydrogen and oxygen atoms. It is defined as the number of hydrogen attached with a particular atom.
In the new concept, valency of an atom is based on the electronic configuration of an atom. According to this concept valency for IA to IVA group element in the periodic table is equal to the number of valence shell electron, and from VA to zero groups it is determined by - (8-noofvalence electron)
Some atoms show variable valency in covalent bonds. Variable valency is shown by that element which has empty orbitals in their outermost shell.
In case of noble gases the valence shell contains eight electrons or fully filled except helium atoms. So there is no free electron present in the valence shell of noble gases or atoms in a stable state, therefore the valency of noble gases is zero. So, noble gases are reluctant to accept electrons from other elements.
This given statement is false.
Note: All the elements in a group have the same valances, because they have the same electronic configuration and the same no of electrons in the valence shell. Noble gases have stable electronic configuration as ns2np6.