1 / 10

Isotopes and Radioactivity

Isotopes and Radioactivity. Isotopes. Isotopes are atoms of an element having the same number of protons but different numbers of neutrons. How many neutrons? Mass number – atomic number = number of neutrons. Sample problems. What is radioactive decay?.

josedaniels
Download Presentation

Isotopes and Radioactivity

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. Isotopes and Radioactivity

  2. Isotopes • Isotopes are atoms of an element having the same number of protons but different numbers of neutrons. • How many neutrons? • Mass number – atomic number = number of neutrons

  3. Sample problems

  4. What is radioactive decay? • This occurs when an unstable atomic nucleus changes into another nucleus by emitting one or more particles and energy • A nucleus that is unstable is radioactive • Radioactive nuclei have found many uses in science and medicine • Iron-59 (an isotope) can be injected into a person’s bloodstream to show blood circulation • pg303

  5. Uses of radioactive decay • Other uses: • Detection of cancer and killing of cancer cells • using coblat-60 to stop the growth of brain tumors • Preserving food • The radiation kills bacteria, fungi, insects, and other pests that spoil food

  6. Discovery • 1896, Antoine-Henri Bequerel -> uranium • Marie Curie separated radioactive elements in uranium mineral • With her husband Pierre, discovered polonium and radium • Most radioactive elements are heavier elements, near the bottom of the periodic table

  7. Half-Life • Uranium is still found in nature because of how long it takes to decay • Half-life is the time it takes for a sample of radioactive isotope to decay to half its original mass • EXAMPLES: • Uranium-235 takes 713 million years

  8. How are elements discovered and named? • Some elements are not found in nature (or found in very small amounts) • Synthetic elements are radioactive elements made by scientists in labs or created during nuclear reactions • Technetium (43) was the first synthetic element • Visualizing Synthetic elements pg 308

  9. Discovery • First they must be discovered and officially confirmed by International Union or Pure and Applied Chemistry and the International Union of Pure and Applied Physics • Write a paper • Experts review the work to support the claims made • Set of rules: must be able to be repeated, following scientific principles, show distinct chemical/physical properties

  10. Naming • Scientists who discover the elements get to name them • They can name after people they want to honor or places of birth

More Related