Completing the table...With a bang

Gabi Andrews

Chapter 6: Synopsis

In chapter six Sam Kean talks about supernovas are responsible for completing the table as we know it today. The periodic table was invented in 1869 by Dmitri Mendeleev. The three elements discussed in this chapter were Cobalt, A student of Ernest Rutherford's, at Manchester University, named Henry Moseley studied elements by blasting them with electron beams. When he shot these electron beams they punched through the atoms own electrons causing a hole (pg. 54). Moseley also discovered the atomic number by mathematically calculating the relation of x-ray wavelengths and the number of protons in the nucleus (pg. 54). Rutherford had the idea of a highly, positive charged nucleus, and two years after the idea was created Moseley proved it to be true. Henry filled the four remaining holes in the table at that time. He also prove there could be isotopes (pg.56). With the help of another one of Rutherford's students, James Chadwick the neutral neutron was discovered. Sadly, during that time scientist had a hard time believing each other during the early 1900's. It was just a big competition on who was right and who was wrong; therefore not a lot of people believed Moseley's discoveries.

By 1940, only one natural element remained to be found, the sixty-first element, no one succeeded until 1949. A group of scientist from the Oak Ridge National Laboratory in Tennessee finally found it. After a couple hundred years of the periodic table was started it was finally completed (pg. 56). Although it was a big discovery they weren't given much praise for it because they were too preoccupied with their work on uranium. Later on, all these elements became handy when the cold war started. America and the Soviet Union were ready if they needed it. The Manhattan project also needed these elements.


Promethium (Pm)

  • Atomic Number: 61
  • Mass: 145
  • Group: 6
  • Electron Configuration: 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 4d10 4f5 5s2 5p6 6s2
  • Classification: Metal
  • Where is the element found: found by uranium fission
  • Who named it: Jacob A. Marnisky, Lawrence E. Glendenin, and Charles D. Coryell
  • This element is important because it can be used to create a nuclear powered battery. It also can be used as an x-ray source, which is helpful to determine broken bones.
  • Who was it named after: Prometheus
  • Unique characteristics: Could be used to make a nuclear powered battery, is the most stable isotope, and promethium-145 has a half life of 17.5 years.
  • Citation: (Thomas Jefferson, 2016)

Plutonium (Pu)

  • Atomic Number: 94
  • Mass: 244
  • Period: 7
  • Electron Configuration: 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14 5s2 5p6 5d10 5f6 6s2 6p6 7s6
  • Classification: Metal
  • Where is the element found: Found by bombarding an isotope of uranium
  • Who named it: Glenn T. Seaborg, Joseph W. Kennedy, Edward M. McMillan, and Arthur C. Wohl
  • This element is important because one of its isotopes can be radioisotope thermometric generators to provide energy for space probes venturing to the sun to use solar power.
  • Who was it named after: Named after the planet Pluto
  • Unique characteristics: plutonium-244 has a half life of 82,000,000 years
  • Citation: (Thomas Jefferson, 2016)

Cobalt (Co)

  • Atomic Number: 27
  • Mass: 59.83
  • Group: 9
  • Period:4
  • Electron Configuration: 1s2 2s2 2p6 3s2 3p6 3d7 4s2
  • Classification: Metal
  • Where is the element found: IT was found trying to prove the color blue in glass was caused by an unknown element
  • Who named it: Gerog Brant
  • This element is important because cobalt60 is important in radioactive isotopes and gamma rays that are used to cure cancer.
  • Who was it named after: It was named after the German word Kobald, which means goblin or evil spirit
  • Unique characteristics: cobalt-60 has a half life of 5.27 years.
  • Citation: (Thomas Jefferson, 2016)

Overall Summary

Overall, these elements are important to us today. Without them we would still be in curiosity. They have helped in history with war, experiments, and other conflicts. These elements also allowed us to know the dangers of something so small. They are a big part of today's world.

Citations