Question

If the radius of the first orbit of hydrogen atom is x Å,
then the radius of the 2nd orbit of hydrogen atom will
be
3x Å
4x Å
6x À
12x À​

Answer 1

If the radius of the first orbit of hydrogen atom is x A°, then the radius of the 2nd orbit of hydrogen atom will be....

solution : according to Bohr's atomic theory,

radius of nth orbit of any atom is given by, r = 0.529 × n²/Z A°

here, Z is atomic no and n is orbit no.

case 1 : first orbit, n = 1, atomic no of Hydrogen, Z = 1

so, radius of the first orbit of hydrogen atom, r = 0.529 × 1²/1 = 0.529 A° = x A°

i.e., x = 0.529 A° .....(1)

for 2nd orbit, n = 2 and Z = 1

so, radius of 2nd orbit of hydrogen atom is given by, r = 0.529 × 2²/1 = 0.529 × 4 A°

from equation (1) we get,

r = 4x A°

Therefore the radius of the 2nd orbit of hydrogen atom would be 4x A°.