Main-group nonmetal ions

The central idea of the ionic bonding model is the tranter of electrons from metal atoms to nonmetal atoms to form ions that attract each other into a solid compound. In most cases, for the main groups, the ion that forms has a fiUed outer level of either two or eight electrons, the number in the nearest noble gas (octet rule). 

In contrast to the nonmetals of the main group, elements the transition metals form only a relatively few compounds that are composed of simple isolated molecules, although they form many complex ions that exist as crystalline solids with an appropriate counter anion. 

This chapter will mainly use examples of coordination phenomena involving transition metals, but where necessary and useful examples may include the coordination behavior of main group metals. There may also be occasion to give examples involving nonmetal systems. The ions used as examples will be both positive and negative ions such as the simple bare metal ions M+ or M , cluster metal ions M and M , and other metal containing ions M E (where E can be another metal, element, or ligand). 

Now we can work out the formula of an ionic compound formed between the monatomic ions of two main-group elements, one a metal and the other a nonmetal. Unless a lower oxidation number is specified (as for the p-block metals), the metal atom loses all its valence electrons, and the nonmetal atom gains enough electrons to complete its valence shell. Then we adjust the numbers of cations and anions so that the resulting compound is electrically neutral. A simple example is calcium chloride. The calcium atoms ([Ar]4s2) each lose two electrons, to form... 

The preferred geometries of carbenium ions and carbanions are correctly predicted by the valence shell electron pair repulsion (VSEPR) theory. The VSEPR theory, which comes from inorganic chemistry, explains the stereostructure of covalent compounds of the nonmetals and the main group metals. It makes no difference whether these... 

To learn how to deduce the formulas of compounds of main group metals with nonmetals, and the formulas of compounds of any combination of metal ion and nonmetal ion if we know the charges on the ions... 

Polonium is the most metallic member of group 6A. But it is not a typical metal. It is rare, radioactive, and extremely toxic. Polonium is important historically because it was discovered by Marie and Pierre Curie in 1898 and named for Marie s nabve land, Poland. Selenium and tellurium are metalloids oxygen and sulfur are nonmetals. There are some trends to note in group 6A. With six valence electrons, the elements act mainly as nonmetals. They tend to gain two electrons to form ions with a 2— charge they also can share two electrons to achieve a stable electron configuration. 

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