Geochemistry

• what are the three main component gases of the atmosphere?

  nitrogen (78%)

  oxygen (20%)

  argon ( around 1%)
• what is the hydrosphere?

  the total amount of water on Earth, including oceans, lakes, rivers, groundwater, and water vapor in the atmosphere.
• what is the Goldschmidt system?


  a classification system for elements based on their atomic structure and positioning in the layers of the earth
• what group of elements remain closest to the surface because they combine readily with oxygen, therefore do not form compounds that sink into the earth: chalcophiles or lithophiles?


  lithophiles
• what group of elements are higher-density transition metals that usually sink to the core because they dissolve readily with iron: siderophile or atmophiles?


  siderophiles
• which group of elements remain on/close to the surface because they readily combine with sulphur and/or some other chalcogen, and therefore do not sink to the core?

  chalcophiles
• what are atmophile elements?

  elements that remain mostly on or above the earth's surface because they occur in either liquids or gases at surface temperatures
• earth was formed by...?

  the collisions of countless meteorites and asteroids. the continuous impact of high velocity space debris meant the Earth remained a molten mass, where elements could then sink, forming the different layers of the earth
• what are stony meteorites composed of?

  silicate minerals
• what are iron meteorites comprised of?

  iron and nickel