The time it takes for a half of the element to decay. In Example: Technetium-99 has a half life of 6 hours. If you begin with a sample of 100g, then after 6 hours you will have 50 grams, at 12 hours you will have 25 grams and so on; however it will NEVER reach 0 (it will remain in exponentially small ammounts because of the asymptote in the graph). This specific exponential decay is shown by the equation y=100(0.5)((1/6)x)
Radioactive elements make up a small fraction of all naturally occurring elements in Earth's crust. Most elements are stable and non-radioactive. However, even though they are a minority, radioactive elements play important roles in various scientific, medical, and industrial applications.
radioactive decay
Elements that emit atomic particles are typically referred to as radioactive elements. These elements undergo radioactive decay and emit particles such as alpha particles, beta particles, or gamma rays as they try to become more stable.
Elements that decay (give off protons and neutrons) to form other elements. *It's not elements as such that are stable or unstable, but rather isotopes. Even elements of small atomic number have unstable isotopes that undergo radioactive decay, for example carbon-14. Elements with higher atomic numbers than Lead (82) are naturally radioactive in all isotopes. Bismuth (83) has an extremely long half-life, but the time generally becomes shorter (the decay more rapid) as the size of the nucleus gets progressively larger for heavier radioactive elements.
No, not all elements have a half-life. Half-life is a property of radioactive elements that undergo decay over time. Non-radioactive elements do not have a half-life because they do not decay in the same way.
many. one example is lead-214 with a halflife of 26.8 minutes.
none, uranium itself is unstable, there are no stable elements after bismuth; and even some researchers suggest that bismuth is an unstable radioactive element with a halflife approaching twice the age of the universe.
halflife
my grandma
no, halflife is a constant for each isotope's decay process.
No, trace elements are not necessarily radioactive. A link to a list of elements that have no natural radioactive isotopes is at a related question, below.
The basic idea is to compare the abundance of a naturally occurring radioactive isotope within a material to the abundance of its decay products; it is known how fast the radioactive isotope decays.
Radioactive elements make up a small fraction of all naturally occurring elements in Earth's crust. Most elements are stable and non-radioactive. However, even though they are a minority, radioactive elements play important roles in various scientific, medical, and industrial applications.
After disintegration all radioactive elements are transformed in other elements.
Not all of the transition elements are radioactive. Many of them are, and some of them have common radioactive isotopes, but some of them have no naturally occurring radioactive isotopes. Please note that all elements have synthetic radioactive isotopes, at least.
Radioactive elements
Radioactive elements exist in all groups of the periodic table.