1 6g sample of He+ ions are excited to emit radiations Spectral study of sample indicates that highest - Chemistry - Atomic Structure

Question

1 6g sample of He+ ​ions are excited to emit
radiations Spectral study of sample indicates that highest excited
state is 2nd and that total no of ions in 1st
and 2nd​ excited state is one third of ions in
ground state Total energy evolved on de-excitation of sample is 429
5kJ Let X be the percentage of He + ions in second
excited stage in original sample Find the value of [X/6 25]

Vartika Jain · Accepted Answer

Dear Student,

Moles of He+=MassAtomic mass                       =1
64                       =0
04 molNow, 1 mol of He+ contains 6
022×1023 ionsSo, 0
04 mol of He+ contains 0 04×6
022×1023 =2
408×1022 ionsHence, total no
 of ions =2
408×1022 ionsLet a be the total ions in 2nd excited state and b be the ions in 1st excited state
 c is the ions in ground state
 So, 13(a+b)=cor, 13a+13b-c = 0      
(i)also, a+b+c=2 408×1022  
(ii)On adding these two equation, we can find the value of a+b and then label the equation (iii)When all the excited ions return to normal state, the energy released= Energy released during deexcitation from II to I+ Energy released during deexcitation from III to Ior, 429
5 × 103 J = [E2-E1]×b + [E3-E1]×aor, 429
5 × 103 = [(-13 622×22-(-13
612×22)]×b + [(-13 632×22-(-13
612×22)]×a On solving these two, one more equation in terms of a+b will be formed which is labelled (iv)and, solving (iii) and (iv) we can get values of a and b and can eventually find the value of X