Posted by Shaniquaa on .
If the wavelength of an electron is equal to the radius of the n=2 orbit in He+, what must the velocity of the
electron be?
The answer is 6.88 x 10^6 m/s
How do I find this? I tried E = Z^2hcRh/n^2 and E= 1/2mv^2 with Z = 1, n=2, m=9.109E31

Chemistry 
Shaniquaa,
nevermind I got it