Q.

Assume that the radius of the first Bohr orbit of hydrogen atom is 0.6Å. The radius of the third Bohr orbit of He+ is _______ picometer. (Nearest integer)         [2023]


Ans.

(270)

rn=r0n2Z

(r1)H=r0(1)21=0.6Å

(r3)He+=r0n2Z

              =0.6(32)2=0.6×92=2.7Å=270 picometer.