Question

the energy of an electron is -3.4ev for H2 atom then the radius of the orbit is

Answer 1

use bohr formula ,
E = -(13.6)Z²/n²
-3.4 = -13.6 × 1/n²
n² = 4

n = 2

hence, orbit no = 2

so, radius of 2nd orbit = (0.529)n²/Z A°
= 0.529 × 4/1 = 2.136 A°