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Chemistry Basics for PSC

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  1. Gold and Platinum are found as native metals.
  2. Antoine Lavoisier wrote the first extensive list of elements, and helped to reform chemical nomenclature. He classified substances into metals and nonmetals.
  3. Johann Dobereiner came up with the law of triads
  4. The law that is similar to octaves found in music is called Law of Octaves. This was found by an English scientist, John Newlands in 1866.
  5. Limitation of Newlands’ Law of Octaves ist that it is applicable only till calcium, after Ca, every eighth element did not possess properties similar to first.
  6. Actinoid element, also called actinide element, any of a series of 15 consecutive chemical elements in the periodic table from actinium to lawrencium (atomic numbers 89–103).
  7. When we move down a group, the number of electrons increases. As the atomic size increases, ionization energy decreases.
  8. The lanthanides are the elements with atomic numbers from 57 to 71. These 15 metals (along with scandium and yttrium) are often called the rare earth elements.
  9. The actinides group includes mostly man-made elements with exceptions such as uranium and thorium.
  10. Electropositive elements tend to lose electrons and form positive ions. Electronegative have tendency to gain electrons to form negative ions.
  11. Electronegativity decreases as you move from right to left across a period on the periodic table.
  12. Electronegativity is a chemical property that describes the tendency of an atom to attract a shared pair of electrons towards itself.
  13. The noble gases are the chemical elements in group 18 of the periodic table. They are the most stable due to having the maximum number of valence electrons their outer shell can hold. Therefore, they rarely react with other elements.
  14. Semiconductors are materials which have a conductivity between conductors and nonconductors or insulators. Examples: Silicon Germanium, gallium arsenide, cadmium selenide.
  15. The 38 elements in groups 3 through 12 of the periodic table are called transition metals.

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