The radius of the first Bohr orbit of hydrogen atom is 0.529 Å , calc

1.	The radius of the first Bohr orbit of hydrogen atom is 0.529 Å , calculate the radii of – (i) the third orbit of He+ ion(ii) the second orbit of Li2+ ion
Answer» Q Radius of n^th Bohr orbit r_n = \(\frac{0.529n^2}{z}\) For H-atom, z = 1, For first orbit n = 1 (i) For He⁺ ion, z = 2, third orbit, n = 3 r₃ = \(\frac{0.529\times(3)^2}{2}\) = \(\frac{0.529\times9}{2}\) = 2.380 Å (ii) For Li²⁺ion, z = 3 Second orbit, n = 2 \(\therefore\) r₂ = \(\frac{0.529\times(2)^2}{3}\) = \(\frac{0.529\times4}{3}\) = 0.7053 Å

The radius of the first Bohr orbit of hydrogen atom is 0.529 Å , calculate the radii of – (i) the third orbit of He+ ion(ii) the second orbit of Li2+ ion

Answer»

Q Radius of n^th Bohr orbit

r_n = \(\frac{0.529n^2}{z}\)

For H-atom, z = 1,

For first orbit n = 1

(i) For He⁺ ion, z = 2, third orbit, n = 3

r₃ = \(\frac{0.529\times(3)^2}{2}\)

= \(\frac{0.529\times9}{2}\)

= 2.380 Å

(ii) For Li²⁺ion, z = 3

Second orbit, n = 2

\(\therefore\) r₂ = \(\frac{0.529\times(2)^2}{3}\)

= \(\frac{0.529\times4}{3}\)

= 0.7053 Å