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Which group contains only radioactive elements?
The actinoids (formerly actinides) are all unstable metallic elements. The period 7 elements with atomic numbers from 89 (actinium, for which the group is named) through 103 comprise these elements. A link can be found below.
What are the first 5 elements by atomic number for which all isotopes are radioactive?
43 Technetium, and 61 Promethium have no stable isotopes. All elements starting at 83 Bismuth have only radioactive isotopes; though Bismuth-209 has such a long half-life that it can be considered stable for any practical purpose.
What is the range of half-lives of different radioactive element?
It would be quite difficult to list all radioactive elements and their half lives in this area. Lithium 5 has a half life of about a trillionth of a second. Uranium 238 has a half life of about 4.7 billion years. Since the world is about 4.2 billion years, over half the Uranium 238 is still around. The first element in the Periodic Table, Hydrogen, has a radioactive form, Hydrogen 3. It has a half life of about Twelve and a half years. Helium has a radioactive form, Helium 5. It's half life is a trillionth of a second. Then you get to elements with different radioactive isotopes. You will need to look them up in a handbook. Tin is the element with the most isotopes.
What is dubnium?
Dubnium is an artificial chemical element, atomic number 105, radioactive, very probably a solid metal, group 5 in the periodic table of elements.
What percentage of a radioactive sample remains after 5 half-lives?
After 5 half-lives, 3.125% (or 1/2^5) of a radioactive sample remains. Each half-life reduces the sample by half, so after 5 half-lives, there is only a small fraction of the original sample remaining.
What are some practical uses for elements in the halogens?
Halogens have various practical uses, such as disinfectants (chlorine), in producing plastics (fluorine), in photography (bromine), and in water purification (iodine). They are also used in manufacturing medicines and chemicals.
What is the radioactive element in period 5?
The radioactive element in period 5 of the periodic table is Actinium (Ac). It is a radioactive metal with atomic number 89.
How Many Radioactive Elements Are Made in the Laboratory?
About 28 elements were discovered in the laboratory. But after the man made preparation some elements were discovered also in nature in very extremely traces: Pm, Tc, Pu, Np, Am, Cm, Bk.
Tritium has a half life of 12.3 years if 118mg escapes what percent of the spill will remian radioactive in 61.5 years?
After 61.5 years, five half-lives would have passed for tritium (12.3 years x 5 = 61.5 years). Each half-life reduces the amount of radioactive material by half. Therefore, after 61.5 years, 3.125% (0.5^5) of the initial 118mg of tritium would remain radioactive.
Why is the number 5 important in Chinese music?
· There are 5 elements: Water, Fire, Earth, Wind, and Metal. · The Tiananmen gate has 5 arches. · The Chinese dragon has 5 claws. · In music, it uses the pentatonic scale (5 notes).
How many subsets of three elements each can be made from a set of five elements?
(5 x 4 x 3)/(3 x 2) = 10
What were the first 5 elements discovered?
The first five elements discovered were gold, copper, silver, lead, and iron. These elements have been known since ancient times due to their distinct properties and uses.
