What keeps electrons from becoming attached to protons in the nucleus?

Answer 1

That is an excellent question. It is in fact one of the key questions that led to the development of quantum mechanics.

Let us consider the hydrogen atom, one proton and one electron. You can reasonably imagine a particle like an electron with an negative charge orbiting a positively charged proton in exactly the same way that a satellite orbits the earth, both the electrostatic attraction and the gravitational attraction being inverse square laws. But an accelerating charged particle (and circular motion with a constant change in direction is an accelerating motion) must radiate energy in accordance with Maxwell's equations. So an electron orbiting a nucleus would be radiating energy, slowing and ought therefore to spiral into the nucleus. But it doesn't and this was a puzzle.

But quantum theory came to the rescue to provide an explanation. de Broglie postulated that all moving objects, like the electron orbiting the nucleus have an associated wavelength.

Bohr proposed that an electron orbiting a nucleus could only have an orbit in which the circumference was an integral number of wavelengths. This implies that there are only discrete energies that are allowable for the electron orbiting the nucleus, and therefore it cannot continually radiate energy away. This theory accurately predicts the emission spectra for hydrogen and provides an explanation for why the atom is stable.

*from a Space.com forum, post by DrRocket

Answer 2

Because electrons move around the nucleus with a greater acceleration. But you may have heard that an electric charge moving with an acceleration should continuously radiate energy causing the atom to collapse. The answer for that is 'energy is quantised'. To say something is quantised means that it comes in well defined,particular quantities which do not change from one value to another smoothly. Rather the change is sudden or abrupt. According to the quantum theory energy is released or absorbed as packets of energy. Consider the hydrogen atom. When it's excited, electron gets energy and it is promoted to a higher energy level. As it is unstable in that energy level it radiates energy as packets and comes to its ground state. In that level it does not have sufficient amount of energy to release as a packet. So it's stable in that level.

Due to the presence of centrifugal force which is equal to the attractive force (force which attract electron to the nucleus) in quantity but opposite in direction. Centrifugal force arises due to the rapid rotation of electron around the nucleus.

According to classical mechanics (Newton's Laws) electrons should be crashing into the nucleus, but they don't. This puzzled the greatest scientific minds into the 20th century. To successfully answer this question they had to develop a new type of science called quantum mechanics.

Quantum mechanics basically says that electrons in no way behave like normal objects. Their ability to constantly make quantum leaps allow them to stay around the nucleus indefinitely.

Even though we can observe and predict the motion of electrons, why they should behave this way continues to be hotly debated.

Electrons remain in their shells, surrounding the nucleus, rather than falling into the nucleus, because they have energy, which is analogous to the angular momentum which keeps planets in orbit around the sun. But note that it is not impossible for electrons to fall into the nucleus. There are some unstable atoms in which this sometimes happens, and it is a form of radioactive decay known as K capture.

Answer 3

The reason why electrons are not pulled into the nucleus of an atom is the same reason that the moon is not pulled into the Earth, and the Earth is not pulled into the Sun.

If the moon suddenly stopped, the attractive force between it and the Earth would pull them together, and they would just collide. On the other hand, if the attractive force between them suddenly stopped, the moon would just fly away into space in a straight line.

As it is, if the moon goes to move past the Earth, the force of gravitation pulls it towards the Earth, and its path curves towards the Earth. If its speed were too high then it would go past the Earth on a curved course, but would not be held in orbit. If its speed were too low then it would spiral in and eventually crash into the Earth. But if its speed is just right, it is held in a stable orbit, which is circular or elliptical.

Its momentum makes it want to move away from the Earth in a straight line, but the attractive force pulls it towards the Earth, and it can't get away. The result is that it stays in orbit around the Earth.

To answer the question about electrons, the same thing happens, except that there is a nucleus instead of the Earth, one or more electrons instead of the moon, and the attractive force between them is electrostatic instead of gravitational.

Answer 4

Electron's are not moving "away" from anything. The distance from an electron to the center of its atom (at least under a simplistic Bohr model) should always be constant assuming no outside forces. While the protons in the nucleus do cause an attractive force on the electrons, the electrons are moving just fast enough in their orbits so that for every unit they are attracted to the nucleus, they travel another unit off to the side, maintaining overall distance.

Answer 5

The protons in the nucleus have a negative charge, the neutrons in the nucleus have a negative charge. so, opposing charges attract.

Answer 6

Electrons are shielded from the nucleus by other electrons which occupy lower energy levels within the atom.

Answer 7

The attraction between positively charged protons and negatively charged electrons is what keeps electrons close by.

Answer 8

This is the electrostatic force. But electrons are not so close.