Halogens alkali metals compared

The (3-diketonate chelate complexes are very stable and exhibit properties which are rather typical of aromatic systems. Many of their reactions such as halogenation, alkylation and acylation can be compared with those of the P-diketonate anions associated with alkali metal cations. However, complexes of transition and other metals add to the stability of the system, so that quite vigorous reaction conditions can be employed. In most of the work carried out on P-diketonate chelates, the modified ligand has not been removed from the metal ion, but this can usually be effected if desired. 

Use the graph of atomic radius versus period number to answer these questions. How does the size of a lithimn atom compare with that of a cesium atom How does the size of a fluorine atom compare with that of an iodine atom Which has the larger radius, lithium or fluorine Based on their atomic radii, which is the most active alkali metal Which is the most active halogen Explain. 

Compare hydrogen with alkali metals and halogens, and distinguish saltlike from covalent hydrides ( 14.1) (EPs 14.1-14.5)... 

As compared to the modem periodic table, the Attempted System is rotated 90° clockwise. The periods are lying vertically, rather than horizontally, and similar elements are grouped in horizontal rows, rather than vertical columns. Notice also that the rows of alkali metals and halogens are adjacent to one another (the noble gases were not yet discovered in 1869). Finally, many of the problematical elements are simply grouped on the right-hand side of the table in no particular order whatsoever. 

Table 3.4 also contains the polarizability volumes of some common monatomic ions. It is seen that removal of the most loosely held electron in an alkali metal atom leads to a dramatic reduction of the polarizability. Similarly, addition of an electron to a halogen atom to form an anion leads to an increase of the polarizability. Comparing cations and anion, we see that halogen anions have considerably higher polarizabilities than alkali metal cations. 

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