Chemical Forums

Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: dolimitless on June 07, 2009, 06:00:22 AM

Title: Why do electrons have more kinetic energy when closer to the nucleus?
Post by: dolimitless on June 07, 2009, 06:00:22 AM
Also similarly, why do electrons have less potential energy when closer to the nucleus?

Please can someone help me and explain in laymen's terms? I don't understand it. I know when electrons are seperated by large distances, they are less likely to interact with the positive charge of the protons of the nucleus. Is that why there is less "potential" energy?

So, there is more kinetic energy (energy due to motion) when electrons are closer to the nucleus, because the electrostatic attraction is greater?
Title: Re: Why do electrons have more kinetic energy when closer to the nucleus?
Post by: Schrödinger on June 21, 2009, 02:16:57 AM
If u consider the Bohr's model of the atom, then the electrons revolve in circular orbits. So there are few formulae that have been derived for the velocity of the electron in the nth orbit.

This velocity is inversely proportional to the radius of the orbit.
U can see that from the eqn : mvr = nh/2(pi)


So, the velocity is greater near the nucleus. And u know that Kinetic energy is
0.5*m*v2.

So, electron has a greater kinetic energy near the nucleus.
Title: Re: Why do electrons have more kinetic energy when closer to the nucleus?
Post by: BluRay on June 22, 2009, 08:05:06 AM
Quote from: dolimitless on June 07, 2009, 06:00:22 AM
Also similarly, why do electrons have less potential energy when closer to the nucleus?

Please can someone help me and explain in laymen's terms? I don't understand it. I know when electrons are seperated by large distances, they are less likely to interact with the positive charge of the protons of the nucleus. Is that why there is less "potential" energy?

So, there is more kinetic energy (energy due to motion) when electrons are closer to the nucleus, because the electrostatic attraction is greater?
If you use a classical decription (not appropriate for electrons in atoms but in this case is acceptable) you can consider the electron as a ball in a hill: the valley is the position nearest to the nucleus, the top is the farthest from the nucleus; when the ball fall down the hill it acquires kinetic energy and loses potential gravitational energy. In the case of the electron and nucleus the potential energy is electrostatic.