# Energy of electrons

1. Feb 19, 2015

### henry3369

So when my book explains energy of electrons it says that the further an electron is from the nucleus the higher the energy, which is why orbitals that are further away have higher energy levels. Then later in the chapter it explains that the greater the distance between two electrons, the lower the energy. I don't understand how the first case is possible. Electric potential energy = kq1q2/r, so increasing distance, decreases the electric potential energy. Also why would the energy of the electron depend on the charges (One situation the energy increases with distance while the other, energy decreases with distance)? Doesn't the sign just denote if it is attractive or repulsive, and the magnitude actually shows the energy?

2. Feb 19, 2015

### proton007007

The sign is important . Comparisons are drawn based on the algebriac value of potential energy .

3. Feb 19, 2015

### PeroK

If a force is attractive, then the further away two particles are, the greater their potential energy.

If the force is repulsive, then the further away two particles are, the lower is their potential energy.

4. Feb 20, 2015

### sophiecentaur

Theexpression "Potential Well" is a good description and a way of remembering which way round the sign goes. Start with zero potential at infinity (great distance) and fall down (negative) you get closer.