1 / 10

Transmutation of Elements

Transmutation of Elements. In 1915 Rutherford realized that elements can be artificially created by bombarding on particles with another particle in a particle accelerator (cyclotron). n. or. 12. Cf + C . Rf + 4. 249. 257. 1. 6. 98. 104. 0. n. 18. Cf + O . Sg + 4.

Download Presentation

Transmutation of Elements

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Transmutation of Elements • In 1915 Rutherford realized that elements can be artificially created by bombarding on particles with anotherparticle in a particle accelerator (cyclotron). n or 12 Cf + C  Rf + 4 249 257 1 6 98 104 0 n 18 Cf + O  Sg + 4 249 263 1 8 98 106 0

  2. Transmutation Practice • Theoretically, you could produce a Au-199 atom if you can effectively collide Re-190 with what other isotope? • If you bombard Au-197 with Co-110, what element would be produced if 4 neutrons resulted?

  3. Half-life Concept • Definition - The time it takes for half a sample of radioactive isotope to decay. • Unlike chemical reactions, the decay of an element is not influenced by pressure or temperature. • Decay is based upon the strong nuclear force being able to overcome the electrostatic repulsion of all the protons in the nucleus. • Nucleus wants to keep that magic 1.5:1 ratio.

  4. Common Elements with Useful Half-life Times • Potassium-40 has a half-life of 1.28 billion years. • Good for dating ancient rocks and minerals • Carbon-14 has a half-life of 5,715 years. • Can only be used to date things that were living. • Iodine-131 has a half-life of about 8 days. • Good for medical tests, specifically related to thyroids.

  5. Half-life Examples Start with 100 grams of a radioactive sample. 1 half-life goes by…. We now only have 50 grams of the radioactive sample. After one more half-life goes by…. We now only have 25 grams of the radioactive sample.

  6. Half - life w/o a formula 1st step, find out the total mass of the original sample 2nd step, find out the length of the half-life 3rd step, cut the total mass in half until you reach your desired time or mass remaining

  7. Half-life Question • Rutherford purchased 25 grams of Cesium-137. If the half-life of Cs-137 is 30 years, how much sample will be remaining after 60 years? How many half-lives? 60/30 = 2. SO… After 1 half-life: (1/2)*(25g) = 12.5g of Cs left After 1 more half-life: (1/2)*(12.5g) = 6.25 g of Cs left

  8. Half-life Questions (cont.) • There is a shortcut… • Formula: r = m (.5)h • r is the amount of sample remaining • m is the mass of the sample at the start • h is the number of half-lives - this can be found by taking: length of time/length of half-life

  9. Half-life Question with Formula… Rutherford purchased 25 grams of Cesium-137. If the half-life of Cs-137 is 30 years, how much sample will be remaining after 60 years? r = 25g (.5)2 r = 6.25 g

  10. Another Half-life Question • A substance has a half-life of 3,000 years. How much of a 40 gram sample will be left after 12,000 years? r = 40g (.5)4 r = 2.5 g

More Related