CG1+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 devised a list of 33 elements known at the time Johann Dobereiner - He attempted to order and organize the elements by their similarities in groups of three Peter Kremers - did you miss this one? Ms. H Jean-Baptist-Andre Dumas - He focused on devising a set of mathematical equations that could account for the increase in atomic weight among several groups of chemically similar elements Alexandre Emile Beguyer de Chancourtois - He postioned the elements according to increasing atomic wieght along the spiral inscribed on the surface of a cylinder and inclined at 45 degrees from the bass John Newlands - He suggested in 1864 that when the elements were ranged 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-a feature that Newlands called "the law of octaves" Julius Meyer - He developed the modern periodic chart almost simultaneously in the late 1860's Henry Mosely - He discovered that the frequencies of features called K-lines in the spectrum of each element were directly 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 included all known elements, overemphasized groups (noble gases), and atomic weights.

3.) What were some of the problems with Mendeleev's table? What discoveries support Mendeleev's Table? Some problems were discovering new elements, whether or not to include the gases in the table, and the order in which the elements would be arranged.

4.) On which properties is the modern periodic table arranged? Atomic number and Average Atomic Mass

5.) Why is it called the __Periodic__ Table of the Elements? Its because the elements are arranged in periods. The period represents the most outer electrons in a shell. What does it mean when something is periodic? Ms. H