woodchurch science

francium was discovered in 1939 by marguerite perey. it occurs as a result of actinium’s alpha decay and can be artificially made by bombarding thorium with protons. it is the heaviest alkali metal. even though it occurs in uranium minerals, it has been estimated that there is only 20-30g of the element present in the earth’s crust at any one time. no weighable quantity of the element has been prepared or isolated. it’s the second rarest element in the crust, next to astatine. it is also the most unstable element.

a small number of pictures of francium have been taken, but only of at the most 350,000 atoms at a time. the images were made by trapping the atoms and using a special fluorescent imaging camera. the atoms were produced by a nuclear transformation with a particle accelerator. the nuclei last for typically three minutes, and must be trapped and observed before they decay.

(and no, we haven’t got any in school, and if we did we wouldn’t put it in water, you’ve seen what potassium does, just use your imagination as to what Fr would do!!)

This entry was posted on Sunday, March 18th, 2007 at 5:06 pm and is filed under chemistry, ks3, ks4, questions, warren. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.