Posted on November 7, 2021
This is an update of my post published on November 7, 2010:
Two different eminent female scientists who did important pioneering work in the field of radioactivity were born on this day. Curie was born Maria Skłodowska in 1867, in Warsaw, Poland (at the time Warsaw was part of the Russian empire); most of her adult life and work were in France. Meitner was born in Austria in 1878, and (because she was Jewish) she later had to flee from the Nazis and ended up in Sweden.
Curie and her husband Pierre did experiments on uranium minerals and discovered two new elements, polonium and radium. Curie won two different Nobel prizes for her work (in Physics and Chemistry)—the first person in the world ever to win two, and still the only woman to win in two different fields. She coined the word radioactivity, invented techniques for isolating radioactive isotopes, and even did the world's first studies on radiation treatment of cancer. Sadly, she died from radiation poisoning.
The chemical element curium (atomic number 96) is named for Marie and Pierre Curie.
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| Radioactive decay |
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Meitner and her colleague Otto Hahn discovered nuclear fission. Although Hahn received a Nobel prize for the discovery, Meitner was overlooked—an omission that many people think is terrible. Meitner and Hahn's work explained why fission released energy, exactly how uranium breaks down into lighter elements, and why no stable elements heavier than uranium exist in nature.
The element meitnerium (atomic number 109) is named for Meitner.
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| Fission is one of the things that are used in nuclear power and nuclear weapons. |
Learn about nuclear physics!
Atoms are basically made up of heavy particles called protons and neutrons, which are found in the center (or nucleus) of the atom, and a surrounding cloud of teensy, almost weightless particles called electrons. A particular element is defined as having a certain atomic number, which is the number of protons that element has.
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Lithium is atomic number 3. It has 3 protons, and it usually has 4 neutrons and 3 electrons. Note that this is a diagram meant to give information - it is not what an atom "looks like." |
If an atom of a particular element loses or gains an electron or two, it is called an ion.
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| Lithium is quite prone to losing an electron. Note that, in this diagram, the protons and neutrons are not visible - they are represented as a single spherical nucleus. |
If an atom of a particular element has more or fewer neutrons than usual, it is called an isotope.
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There are two naturally occurring isotopes of lithium. Much more common is the lithium that has 3 protons and 4 neutrons - each of which are considered to weigh 1 in atomic weight; so the most common lithium has an atomic weight of roughly 7. Some lithium, however, has 3 protons and only 3 neutrons; its atomic weight is roughly 6. These isotopes of lithium are called lithium 7 and lithium 6. |
But if an atom of a particular element loses or gains a proton—it becomes another element!
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| If lithium were to somehow lose a proton, it would become helium (which has 2 protons), above. If lithium were to somehow gain a proton, it would become beryllium (which has 4 protons), below. |
- Check out this wall chart. Click on sections to see the details and read the text! Then use the online teacher's guide to the wall chart to find out more.
- For even more, use the Experiments section of the “ABCs of Nuclear Science.”
- For more on Marie Curie, see this earlier post (scroll down).
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