Periodic Trends Lab Report

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Purpose: The purpose of the lab was to identify seventeen unknown elements, while using limited information that was presented. Secondly, describe the periodic trends and how each of the properties given changes as you go across a period or down a group. Lastly, to explain how Mendeleev used the properties known to predict the existence of undiscovered elements and use this information to explain their specific properties. Independent Variable: The unknown and known elements given to organize. Dependent Variable: The order of elements arranged due to trends and properties. Constants: The periodic trends must be followed for every period and group. The known elements must be placed accordingly. The order of elements that were …show more content…

This means that all of the elements in the same group have a main aspect in common, except for a few exceptions. These elements react with the same specific compounds. This was used to identify the order of the groups from left to right and to determine which elements go under which group. Some research was conducted to identify all the names of the groups ranging from element number one to element number 20. Once all group names were recorded, it was researched which groups react with which compounds that are given on the element cards. For example, it was found that the alkaline earth metals react with O₂ to form XO. From this information, all elements with this reaction could be classified under the second group of elements. Next density was the last deciding factor to determine which elements go into which group. This only needed to be done for hydrogen and fluorine as they were the two elements that did not follow the periodic trend of reacting with similar compounds to form similar reactants. For hydrogen, it is known it is the lightest element from looking at the periodic table, determining it to be the least dense. So, from the two elements left from groups, the element with a density of .0001 g/cm³ was determined to be hydrogen. This was proven to be correct when the density of hydrogen was researched to be sure. This left the final unknown element as fluorine and the density was found to make sure the groups were being formed correctly. So, fluorine was placed in the 7th group on the periodic table being formed and hydrogen in the

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