Question

the energy of first excited state of li2+ will be

Answer 1

Hey There,
Here Lithium has been given in a +2 excited state. 

This question pertains to Bohr's Theory. 
For Hydrogen-like species, the energy is given by:   

E = -(me⁴) / (8ε²h²n²)
On putting values, we have:  

E = -13.6 * (Z²/n²)
Here, We are considering Lithium. So, Z=3
Also, First Excited State is n=2 
Plug in the values, you have your answer: 
E = -13.6 * (9/4) = -30.6 eV

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