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Chemistry Forums for Students => High School Chemistry Forum => Topic started by: Noctorne on April 08, 2011, 07:54:45 PM

Title: Bohr Model Energy Levels
Post by: Noctorne on April 08, 2011, 07:54:45 PM

I'm really confused in chem class right now.  My teacher gave us an equation to solve for the energy, 'E', of an electron orbiting a hydrogen nucleus, provided you are given the energy level, 'n', and the constant 'k' (k=2.18 x 10^-18 J).  The equation is as follows:

E = - k/n^2

What I don't understand is how the energy is inversely proportional to the energy level, because I would have thought a higher energy level would mean more energy.  Can anyone please explain this equation to me?

Much appreciated

Title: Re: Bohr Model Energy Levels
Post by: Schrödinger on April 08, 2011, 11:59:13 PM

Please note the negative sign. This means that the system is bounded, i.e, the nucleus attracts the electrons and hence the energy of the system is negative. But as we move further away from the nucleus, this energy becomes less negative. That is to say, the nucleus' force of attraction on the electron decreases. When n approaches infinity, the energy of the system = 0. The electron is now free. So, technically speaking, the energy is in fact, increasing.