Question

assume that the electron in li++ ion in third orbit calculate the total energy of the electron ?

Answer 1

you should apply bohr's radius formula i.e.,52.9n square/z and the answer is 158.7pm
energy is2.14×10power-18

or in simple way

Energy of the electron = -13.6·Z²/n² eV 
= -13.6(3)²/(3)² 
= -13.6 eV 
= 21.72 × 10^-19 J

Answer 2

TE=-13.6$\frac{z^{2} }{n^{2}}$ eV
TE=-13.6X9/9
TE=-13.6eV