Closure temperature radiometric dating
The Be nucleus (Beryllium-7) is an electron capturer with a half-life of about 53 days, turning into Lithium-7. While this half-life is way too short to be useful for radiometric dating, the effect of the chemical state is noticeable.The reason is that, because the atomic number is only four, the 2s valence electrons are very close to the 1s electrons involved in capture.With uranium-lead dating, for example, the process assumes the original proportion of uranium in the sample.One assumption that can be made is that all the lead in the sample was once uranium, but if there was lead there to start with, this assumption is not valid, and any date based on that assumption will be incorrect (too old).In fact, it is possible to shut down electron capture completely—simply ionize the substance so that there are no electrons nearby.
It is more accurate for shorter time periods (e.g., hundreds of years) during which control variables are less likely to change.
For these reasons, if a rock strata contains zircon, running a uranium-lead test on a zircon sample will produce a radiometric dating result that is less dependent on the initial quantity problem.
Another assumption is that the rate of decay is constant over long periods of time.
Any incoming negative charge would be deflected by the electron shell and any positive charge that penetrated the electron shells would be deflected by the positive charge of the nucleus itself. "Decay" simply refers to a meson or baryon becoming another type of particle, as the number of a certain type of particle goes down or decays as they are converted.
This can happen due to one of three forces or "interactions": strong, electromagnetic, and weak, in order of decreasing strength.