If they can begin to comprehend that it is random and spontaneous, they end up feeling less nervous about the whole thing. Radioactive decay involves the spontaneous transformation of one element into another.
The only way that this can happen is by changing the number of protons in the nucleus an element is defined by its number of protons.
There are a number of ways that this can happen and when it does, the atom is forever changed. There is no going back -- the process is irreversible. This is very much like popping popcorn.
When we pour our popcorn kernels into a popcorn popper, the is no way to know which will pop first. And once that first kernel pops, it will never be a kernel again And coincidentally, much yummier! The atoms that are involved in radioactive decay are called isotopes. In reality, every atom is an isotope of one element or another. However, we generally refer to isotopes of a particular element e.
The number associated with an isotope is its atomic mass i. The element itself is defined by the atomic number i. Only certain isotopes are radioactive and not all radioactive isotopes are appropriate for geological applications -- we have to choose wisely.
Those that decay are called radioactive or parent isotopes; those that are generated by decay are called radiogenic or daughter isotopes. The unit that we use to measure time is called half-life and it has to do with the time it takes for half of the radioactive isotopes to decay see below.
Half-life is a very important and relatively difficult concept for students. However, carbon, with six protons and eight neutrons, is unstable or radioactive. The number of neutrons for a carbon nucleus is too high for the strong attractive force to hold it together indefinitely. But, as you move to atoms that contain more protons, isotopes are increasingly stable with an excess of neutrons.
This is because the nucleons protons and neutrons aren't fixed in place in the nucleus, but move around, and the protons repel each other because they all carry a positive electrical charge. The neutrons of this larger nucleus act to insulate the protons from the effects of each other. The ratio of neutrons to protons, or N:Z ratio, is the primary factor that determines whether or not an atomic nucleus is stable.
There are also what are called magic numbers, which are numbers of nucleons either protons or neutrons that are especially stable. If both the number of protons and neutrons have these values, the situation is termed double magic numbers.
You can think of this as being the nucleus equivalent to the octet rule governing electron shell stability. The magic numbers are slightly different for protons and neutrons:. To further complicate stability, there are more stable isotopes with even-to-even Z:N isotopes than even-to-odd 53 isotopes , than odd-to-even 50 than odd-to-odd values 4.
One final note: Whether any one nucleus undergoes decay or not is a completely random event. The half-life of an isotope is the best prediction for a sufficiently large sample of the elements. It can't be used to make any sort of prediction on the behavior of one nucleus or a few nuclei. Can you pass a quiz about radioactivity?
Actively scan device characteristics for identification. Use precise geolocation data. Select personalised content. As for the exponential decay: a nucleus falling apart is stochastic process, meaning it is only dictated by chance!
Then, you can add more nuclei the chance of half of them decaying after it's half life is far, far larger than all of them being stable. The larger amount you start of with, the better this theory describes the decay. If you then measure a vast amount of atoms a mole for example the curve you find will describe an exponential decay. Sign up to join this community.
The best answers are voted up and rise to the top. Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Learn more. Why does radioactive decay occur? Every once in a long while, however, the jiggles might line up or form a resonance that sends the nucleus across the limit of its cohesion, and the nucleus splits.
A nuclide with a shorter half-life less stable will violate its binding energy sooner, statistically, than will a nuclide with a longer half-life more stable. A stable nuclide will never violate its binding energy without the addition of outside forces. If the pail is nearly empty, it is stable, and water will not slosh out. If it is full to the brim, it is unstable, and some water is certain to slosh out.
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