Uncertainty Principle and minimum kinetic energy

[cwatki14]

An atom represents a region about 1.7 10-10 m wide in which an electron is confined. Use the Heisenberg uncertainty principle to estimate the minimum kinetic energy of the electron, expressing your result in electron-volts (eV).

So I got the problem right when I analyzed the atom as a 1 d region. How will this change if it is a 3d region? I found minimum momentum=h/$$\Delta$$x
and then used the equations KE=p^2/2m...

 

[Redbelly98]

Can you write p² in terms of p_x, p_y, and p_z?