And if a proton is 2 up/ 1 down, and a neutron is 1 up/ 2 down, then how in the world are electrons attracted to the protons?
In: 7
Nuclear force keeps them together. It’s strong enough at very close proximities to overpower the magnetic forces pushing the protons away from each other
To understand why electrons are attracted to the proton, you just need to look at the charges of those quarks.
In elementary units an up quark has a charge of +2/3, a down quark a charge of -1/3. 2/3+2/3-1/3 = 1. So a proton has a net charge of +1. Meanwhile an electron has an electric change of -1. Opposite charges attract and so the electron and proton are attracted to one another.
As for the proton and the neutron, they are attracted by the residual strong nuclear force. This is a force between any particle made up of quarks, regardless of electric charge as it is a separate force entirely from electromagnetism.
It’s something called the strong nuclear interaction that is only effective at around 3fm that is an attractive force stronger than the electrostatic repulsion of the protons from each other. This also acts as a repulsive force below 1fm to prevent the nucleus from collapsing into a point
Neutrons are *electromagnetically* neutral. But there are other forces out there besides the electromagnetic force. For neutrons and protons, there is the strong nuclear force, which is much greater than that of the electromagnetic force, but only operates on much smaller distances.
Both neutrons and protons are made up of quarks, as you note. The up quark has a positive 2/3rds charge and the down quark has a negative 1/3rd charge. This means the proton has an net positive charge of 1 (2/3 + 2/3 – 1/3 = 1) and the neutron has no net charge (2/3 – 1/3 – 1/3).
Each electron has a net negative charge of 1, and is electromagnetically attracted to the positive charge of the proton.
Think of the proton and neutron as small little balls covered in Velcro.
If they’re not that close nothing much will happen. But after getting close enough they will stick together.
The Velcro is the strong force.
Latest Answers