Half life


The concept of half-life deals with the time required for the activity of a radioactive element to be halved. A good example for this concept is the dating of fossils where carbon - 14 dating is used as comparison parameters.

This concept is important for various purposes, such as determining the age of fossils.

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Periodic table

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The elements were organized by the professor of the University of St Petersburg, Dimitri Ivanovich Mendeleev, who wrote a book about the chemical elements, were about 63 elements, and Mendeleev organized them by function of the mass of their atoms establishing families and groups. The elements in the table are organized horizontally, in numerical sequence, according to their atomic numbers, and are organized through periods and families. There are seven periods in the table and the amount of electronic layers that the chemical elements present is indicated by the period number, they represent the horizontal rows of the table.  References: Periodic table families. Link: http://www.tabelaperiodicacompleta.com/familias-da-tabela-periodica, 2017. Access on March 13, 2017.
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Chemical Reaction:6 CO 2 + 6 H 2 0 => C 6 H 12 O 6 + 6 H 2 O The chemical reaction that basically occurs in photosynthesis is that the plant captures sunlight through the pigments in the leaves, absorbs water and minerals from the Earth by the root of the plant and also absorbs the carbon dioxide from the air, passing through a chemical reaction, releasing the oxygen we breathe, and producing the sugar that is its food. References:  Fogaça, J.   Chemical Reaction of Photosynthesis. Website: http://brasilescola.uol.com.br/quimica/reacao-quimica-envolvida-na-fotossintese.htm , 2017. Access on March 13, 2017.
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