One mole of triatomic gas and three moles of a monoatomic gas contain same number of atoms.
Mole concept
n=NNa(N=No.ofelementaryentity,NA=Avagadronumber)
N=nXNAXAtomicity
N=1x6.022x1023x3=18.066x1023
N=3x6.022x1023x1=18.066x1023
Hence, the given statement is True i.e., One mole of triatomic gas and three moles of a monoatomic gas contain the same number of atoms.
One mole of a triatomic gas contains 6.022×1023atoms