Derive an expression similar to the equation for the energy levels above for the single electron in He + and Li2+. Calculate the numerical values for the 1s levels (n = 1) ?

from Bohr's equation,

E = - Z²R/n²

R = 13.6 eV

Z = atomic number of element

for 1s energy level n = 1

E = - (Z) ² x (13.6) / (1) ²

E = - 13.6Z²

calculating the numerical for the 1s energy levels for He + and Li2+

- for He+

E = - 13.6 * (2) ² = - 54.4eV

- for Li2+

E = - 13.6 * (3) ² = - 122.4eV