Bohr radius for single electron orbits

[xiankai]

for ions with more than one proton ie. He⁺, Li²⁺ and Be³⁺, doesn't the extra charge factor into the equation? because it seems only the elementary charge is http://en.wikipedia.org/wiki/Bohr_radius" , hence rendering it independent of amount of positive charge present.

 

[jtbell]

for ions with more than one proton ie. He⁺, Li²⁺ and Be³⁺, doesn't the extra charge factor into the equation?

Yes. For ions with a single electron but $Z$ protons, replace $e$ with $Ze$, where $e$ is the unit charge $1.60 \times 10^{-19}$ C.

Most textbooks do the derivation with hydrogen in mind, and later make the above correction for heavier, hydrogen-like ions.

 

[xiankai]

got it. thanks for the quick reply!