`1.8 g` hydrogen atoms are excited by a radiation. The study of species indicates that `27%` of the atom are in third energy level and `15 %` of atom in second energy level and the rest in ground state. If IP of H is `13.6 eV`, calculate
a. Number of atoms present in first and third energy levels
b. Total energy involved when all the atoms return to the ground state.

Answer

`292.68xx10^(21)` atom.`162.60xx10^(21)` atoms,`832.50kJ`

Explanation

`1.8` mole = `(1.8Na)` atoms
`27%` =IIIrd energy level `=1.8xxNaxx0.27`
`15%` =IInd energy level `=1.8xxNaxx0.15`
`DeltaE = overset(DeltaE_(1))(3rarr1)+overset(DeltaE_(2))(2rarr1)=1.8xxN_(A)xx0.27xxIE[(1)/(9)-(1)/(1)]+1.8xxN_(A)xx0.15xxIE[(1)/(4)-(1)/(1)]=292.68xx10^(21)`atom