The ratio of the radii of first orbit of H, He+ and Li2+ is?

1 Answer
Jun 13, 2017

The radii are in the ratio 6:3:2.

Explanation:

The radii of the first orbits of a hydrogen-like ion are given by the equation

r = (ħ^2)/(Zm_ek_ee^2)

Since everything except Z is constant, we can rewrite the formula as

r = k/Z

Then the ratios of the three radii for Z = 1, 2 and 3 are

r_1:r_2:r_3 =1/1:1/2:1/3 = 6:3:2