Q.

The energy of an electron in the ground state (n=1) for He+ ion is -x J, then that for an electron in n=2 state for Be3+ ion in J is         [2024]

1 -x  
2 -x9  
3 -4x  
4 -49x  

Ans.

(1)

En=-RHZ2n2

For ground state He+ ion, Z = 2, n = 1,

        E1=-RH2212=-4RH=-x J

For an electron in n = 2 state for Be3+ ion (Z = 4),

        E2=-RH4222=-4RH=-x J