CG2+Evolution+of+the+Periodic+Table

Answer the questions, in complete sentences based on the article from Scientific American "The Evolution of the Periodic System".

1.) For each scientist listed, describe the contribution to the development of the periodic table. Antoine Lavoisier - he made a list of the 33 elements at that time Johann Dobereiner - Noticed that the 3 members of the triad were ordered by atomic weights. Peter Kremers - Suggested that that certain elements could belong to two triads placed perpendicularly Jean-Baptist-Andre Dumas - He focused on making a set of mathematical equations that could account for the increase in atomic weight amongst several groups of chemically similar elements. Alexandre Emile Beguyer de Chancourtois - Positioned the elements according to increasing atomic weight inscribed on the surface of a cylinder. John Newlands - Suggested in 1864 that when the elements were arranged in order of atomic weight, any one of the elements showed properties similar to those of the elements eight places ahead and eight places behind in the list Julius Meyer - Produced a periodic table that turned out to be remarkable similar to Mendeleev's but failed to classify the elements correctly. Henry Mosely - Discovered that the frequencies of features called K-Lines in the spectrum of each element were proportional to the squares of the integers representing the position of each successive element in the table.

2.) What properties did Mendeleev use to arrange his periodic table? -He had 63 elements and positioned them according to atomic weight. He also left spaces for undiscovered elements. 3.) What were some of the problems with Mendeleev's table? What discoveries support Mendeleev's Table? - All the scientists listed supported Mendeleev's Table. 4.) On which properties is the modern periodic table arranged? - The periodic table has space for 118 but only 112 have been discovered to date. 5.) Why is it called the __Periodic__ Table of the Elements? - Periodic reflects the fact that the elements show patterns in their chemical properties in certain regular intervals.

Nice job! Ms. H