|
Monthly Archive - August 2016 (page 18)brain teasers, puzzles, riddles, mathematical problems, mastermind, cinemania... These are the tasks listed 171 to 180. |
Top 10 Users (1174)
| 1. |  |
H Tav | 5861 |
| 2. |  |
c. raj. | 5777 |
| 3. |  |
Nasrin 24 T | 5731 |
| 4. |  |
Fazil Hashim | 5718 |
| 5. |  |
Thinh Ddh | 5557 |
| 6. |  |
Alfa Omega | 4681 |
| 7. |  |
Djordje Timotijevic | 4549 |
| 8. |  |
Mita Kojd | 4525 |
| 9. | Jakubovski Vladimir | 4443 |
|
| 10. | Chandu Rajyaguru | 4419 |
See full ranking list
Kasimir FajansDied 18 May 1975 at age 87 (born 27 May 1887). Polish-American physical chemist who discovered the radioactive displacement law simultaneously with Frederick Soddy of Great Britain. According to this law, when a radioactive atom decays by emitting an alpha particle, the atomic number of the resulting atom is two fewer than that of the parent atom. He discovered several elements that are created through nuclear disintegration. The first discovery of protactinium was in 1913 by Kasimir Fajans and O. Göhring, who found the isotope protactinium-234m (half-life 1.2 min), a decay product of uranium-238; they named it brevium for its short life. (Protactinium-231 was later identified in 1918 by other scientists; the name protoactinium was adopted at this time.) |
This site uses cookies to store information on your computer. Some are essential to help the site properly. Others give us insight into how the site is used and help us to optimize the user experience. See our privacy policy.