Such became his law of periodicity if you arrange

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: tals: LUMO+ 0 1, 2, 3 Shell/subshell 5s 5p Energy Shape* *Notice that inner shells may not appear correct because of approximations and scale. Dakota State University Page 100 of 232 Experiment 8: Periodicity General Chemistry I and II Lab Manual Experiment 8: periodicity Purpose: To observe what is meant by “periodicity” and relate periodicity to electronic configuration Perv: I think we ALL know a few people who fit into this category Background: None Introduction: In 1869, Russian Scientist Dmitri Mendeleyev was busy considering chemical and physical properties of the known elements, and trying to find an underlying order to them. At this time, very little was known of atomic structure, and the concept of atomic number had not yet been proposed. However, a table of atomic masses were published by Stanislao Canizzaro, which Dmitri used to arrange the elements. Then, he noticed an odd thing; if he arranged the lists of elements in a table, based on atomic masses, the properties of the elements in any given column were similar to one another. Such became his “Law of Periodicity”; if you arrange elements according to atomic mass, the chemical and physical properties of these elements will repeat in a periodic fashion. Now we understand his error; the elements are not arranged according to atomic mass, but rather according to atomic number. Careful examination of the periodic chart will show that there are only a handful of pairs of elements that are in their incorrect spots if you arrange the table according to atomic mass, however, so Mendeleyev’s creation was adopted and exists even today as the basic form of the periodic chart. Our purposes today are two- fold: (1) we wish to elucidate several of the trends of the periodic chart, and (2) we wish to learn of some of the on-line tools available to the chemist. Experimental Methods: Part I: On-Line Tools You will be given a presentation of current on-line resources available to chemists. In your lab manual, take note of these URL addresses, and the specific role of each site (a.k.a. the type of information each web site provides). Part II A: Periodicity Dakota State University Page 101 of 232 Experiment 8: Periodicity General Chemistry I and II Lab Manual For this part of the project, you may split this work with your lab partner and no more than one additional group (five people maximum), but you must report the data that you personally were responsible to obtain. Write down the information you obtained in your own lab notebook, and don’t forget to give the URL address or reference the source from which it was obtained. This is an on- line project, so do not use any print resources (unless they are fully available on- line as well). With the other people you are working with, obtain the following information: For the first 18 elements (H through Ar), find the atomic radii, melting points, boiling points, electronegativities, and first ionization energies. Graph this data in your lab notebooks in accordance with the calculations section. Part II B: ON YOUR OWN, find the following information for the Oxide of ONE O...
View Full Document

This note was uploaded on 09/18/2012 for the course CHEMISTRY 1010 taught by Professor Kumar during the Fall '11 term at WPI.

Ask a homework question - tutors are online