Question

which transition of Li^2+ is associated with same energy change as n=6 to n=4 transition in He+ . ( the options are given above in the attachment).​

Answer 1

Explanation:

This is because the energies of the 2nd, 4th, and the 6th orbits in He⁺ are equal to the energies of the 3rd, 6th, and the 9th orbits in Li²⁺ respectively. The corresponding transition from 9 → 6 in Balmer series of Lithium atom has the same frequency as that of 6 → 4 transitions in He