What is the degrees of freedom of helium gas ?

[thereddevils]

what is the degrees of freedom of helium gas ?

shouldn't helium gas be diatomic ? If so , it will be 5 .

i have problems differentiating monoatomic and diatomic . Though its obvious that mono is one atom and diatomic is 2 atoms . Is it possible to know whether its mono or diatomic from the periodic table ?

 

[kuruman]

Helium is monatomic and is called a "noble" gas for that reason. All gases in the same column below helium in the periodic table are noble gases.