Why do protons and electrons not collide

Why don't the electrons zip directly into the nucleus and stick to the protons? Everyone who has ever sat through fourth grade knows that when you rub a balloon on your hair, or your sweater, you can stick it to the wall.

You can do this because the rubbing caused the balloon to accumulate a lot of electrons. Electrons are attracted to protons, and repelled by other electrons, so when the balloon was pushed near the wall, the electrons in the wall rushed away, leaving exposed protons. These half-naked protons were irresistible to the electrons in the balloon and the electrons rush towards the protons, taking the balloon with them.

The question is, why did those electrons move from your hair to the balloon in the first place? If they were so smitten with protons, they had plenty of them right there in your hair. Uncharged atoms pair equal amounts of electrons and protons. The electrons should zoom right to the atomic nucleus. In classical physics, electrons should fall into the nucleus even if they weren't attracted by the charge of the proton. Early models of atoms had electrons orbiting the nucleus the way a planet orbits a sun.

Orbiting in a circle means making a lot of changes of direction- which means acceleration. When an electrical charge undergoes acceleration it gives off electromagnetic radiation. Electromagnetic radiation is energy, and the electron can lose one of two kinds of energy; kinetic energy or speed , or potential energy or distance from the nucleus.

Either way, it will eventually crash into the nucleus. Let us think of a single electron floating in space. How do we even measure its kinetic and potential energy? Start by imagining a single proton, far away. Together, they can unite and form a hydrogen atom. As we measure their progress towards each other, in terms of energy, we will see in many ways what we see in classical physics. Because of the wavelengths, the two particles essentially do touch each other.

Under extraordinary conditions, protons do stick to electrons. The high pressure within a neutron star forces electrons and protons to react to form neutrons. Within about 14 minutes, the free neutron decays to form a proton and electron, which in turn form an atom of hydrogen. Search for:. Electrons can get localized in the nucleus, but it takes an interaction to make it happen. The process is known as "electron capture" and it is an important mode of radioactive decay.

In electron capture, an atomic electron is absorbed by a proton in the nucleus, turning the proton into a neutron. The electron starts as a regular atomic electron, with its wavefunction spreading through the atom and overlapping with the nucleus.

In time, the electron reacts with the proton via its overlapping portion, collapses to a point in the nucleus, and disappears as it becomes part of the new neutron. Because the atom now has one less proton, electron capture is a type of radioactive decay that turns one element into another element. If the question was supposed to ask, "Why is it rare for electrons to get localized in the nucleus? An electron will only react with a proton in the nucleus via electron capture if there are too many protons in the nucleus.

When there are too many protons, some of the outer protons are loosely bound and more free to react with the electron. But most atoms do not have too many protons, so there is nothing for the electron to interact with.