Li+2 ion is hydrogenic and has a Lyman seriies at 740747cm-1,877924cm-1,925933cm-1 and beyond.Show tht the energy levels are of the form -R/n2 and find the value of R for this ion. Predict the wave no's of the two longest wavelength transition of the Balmer series of the ion and find the ionisation energy of the ion?
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2 Answers
621/λ1=R(1/1-1/22)
1/λ1=.75R
1/λ2=R(1/1-1/32)
1/λ2=8/9R
1/λ3=R(1/1-1/42)
1/λ1=15/16R
Now take the ratios
1/λ1:1/λ2:1/λ3 = 4/3:9/8:16/15
we compare the lamda's above.. the ratio is the same..
so we have shown that the energy levels are as needed!
621/λ1=R(1/1-1/22) = 4/3R
We know λ1
so we know R
last part follows simply by taking appropirate n1 and n2