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There are fewer decays because there are fewer atoms to decay The simple reason why the number of decays (strictly, the number of decays per unit time) decreases in simple radioactive decay is because there are fewer atoms left to decay. Nuclear decay is probabilistic. The probability of any given unstable atom decaying is constant (independent of time or ...


8

For energy levels in nuclei (and their gamma emission) the first place to look is at the Evaluated Nuclear Structure Data Files. I usually use the Brookhaven site, but there may be a closer mirror to you. Enter 24 into the Nuclide or Mass box and hit Enter. Check the 'Adopted Levels, Gamma' box by $^{24}$Mg, and request the pdf version (back up at the top). ...


5

It is a general principle, not limited to nuclear chemistry, but is common for many areas, e.g. for the reaction kinetic of the 1st order. All processes, where the value time rate is proportional to the value, have value time evolution in the form of the exponential function. $$\frac {\mathrm{d}x}{\mathrm{d}t}= -k \cdot x$$ leads to $$x= x_0 \cdot \exp {...


5

The Rutherford formula, as derived, assumes purely elastic scattering from the Coulomb force. No formation of a compound nucleus is considered. Generally, for most of the initial experiments, the available alpha particle energies from various decays (in the range of a few MeV) were not high enough for large deviations from pure Rutherford scattering. Of ...


3

Let's look at just the carbon-14 atoms. Assune 18.5% of your body mass is carbon and you weigh 80 kg. One carbon atom in a trillion is carbon-14. Working out the resulting mass of carbon-14 atoms in grams, dividing by 12.01 g/mol and multiplying by Avogadro's Number leads to roughly $7.4×10^{14}$ atoms. Carbon-14 has a half-life of about 5730 years. ...


1

The Currie algorithm* for the calculation of the minimum detectable activity (MDA) is generally considered obsolete. Today, detection limits are calculated according to ISO 11929 and related standards (for example, see also https://chemistry.meta.stackexchange.com/a/3283/7951) Nevertheless, when using the Currie MDA algorithm, the detection limit $L_\mathrm ...


1

Deuterium is a stable combination of a proton and a neutron, but it could accept and bind a proton, forming helium-3 or a neutron, forming tritium. Neither reaction would be explosive, in the sense of liberating enough energy to cause some other nuclear reaction. You might be able to make a small explosion as the sudden heat boils something very fast. Now, ...


1

In a sense, atoms are "going nuclear" all the time, forming radioactive isotopes under the influence of high-energy particles in the upper atmosphere. In perhaps the best-known example, the bombardment of nitrogen with high-energy neutrons may generate carbon-14, which subsequently enters organic matter before it slowly decays (half-life = 5700 years), ...


1

Decaying are like coin tossers It helps me to compare two different mental pictures. The first picture, which is not at all like radioactive decay, is of lighting a fuse. It starts burning at the near end and burns toward the far end at some number of millimeters per second. Each section's chance of burning depends completely on the section before it: the ...


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