How much energy is required to move the electron sufficiently far away from the proton such that it does not experience the proton's electric field. Express your answer in units of Joules.

Question

parthkohli · Answer

Do you know the formula for energy in Bohr's Model?

anonymous · Answer

Ya....

parthkohli · Answer

$$E = -\dfrac{Z^2}{n^2} 13.6 ~\rm J$$

parthkohli · Answer

You want to excite the electron to $0 \rm J$

anonymous · Answer

But, shouldn't I use the value of bohr radius for the initial distance between the electron and proton ?

parthkohli · Answer

You can.

anonymous · Answer

And what value of Z should I use? the question doesn't say anything about the atomic number or the element? Should I use Z=1 as in Hydrogen?

parthkohli · Answer

You want the electron and proton to not be affected by each other's electric field.  This is possible only at infinity.  If the radius in $\infty $, then the energy is $0~\rm J$.  So you can directly apply the formula for energy.

parthkohli · Answer

I think you should leave $\rm Z$ as it is.

parthkohli · Answer

$$\Delta E = E_f - E_i = \dfrac{Z^2}{n^2}\left(13.6\right) ~\rm J$$

anonymous · Answer

Ok, I think I got it! thanx for your help!

parthkohli · Answer

Just for confirmation, what answer does it give in your book?

parthkohli · Answer

@Sourav12084 Oh my God... lol, I gave you the answer in eV.  Convert eV to Joules.

parthkohli · Answer

Multiply that expression by $1.6 \times 10^{-19}$

anonymous · Answer

The question wasn't from a book...my teacher gave it for homework...and yea...i converted the answer in joules already...thanx a lot for your help...