Sometimes, after its emission of an alpha, beta or positron particle, the nucleus is still in an excited state, called a metastable state.
In order to get to a lower energy state it emits a quantum of energy in the form of a gamma ray.
Here's a picture of the nucleus, with two protons and two neutrons, and we know it's stable, even though we know like charges repel. We know that this nucleus is stable, so there must be something else holding the nucleus together, which we call the strong force.
And so these two protons are repelling each other, and that's the electrostatic force. So the nuclear strong force is stronger than the electrostatic force.
- [Voiceover] In the last video, we talked about the helium nucleus, which contains two protons and two neutrons.
Protons and neutrons in the nucleus are called nucleons, and so I'll use that term a few times in this video.
The radiation produced during radioactive decay is such that the daughter nuclide lies closer to the band of stability than the parent nuclide, so the location of a nuclide relative to the band of stability can serve as a guide to the kind of decay it will undergo. A nucleus of uranium-238 (the parent nuclide) undergoes α decay to form thorium-234 (the daughter nuclide).
The spontaneous change of an unstable nuclide into another is radioactive decay.
The reactants are shown on the left, and the products are shown on the right.
In this lesson, we are going to learn to write nuclear equations to symbolize the changes that take place in the nucleus during a nuclear reaction.
This is not a highly unstable state otherwise the emission of the gamma ray would accompany the alpha, beta or positron particle.
Nuclei in the metastable state produce gamma rays at a measurable half-life.