Properties of Other Main Group Elements

The aluminum oxide forms a protective coating, preventing the underlying metal from reacting further. This fact makes it possible to use aluminum for stmctural materials, such as aluminum siding and the shells of airplanes. Without the protective coating, layo- after layer of Al atoms would become oxidized, and the structure would eventually crumble. 

Aluminum forms the Ap ion. It reacts with hydrochloric acid according to the equation  

The other Group 3A metals (Ga, In, and Tl) can form both M and ions. As we move down the group, the M ion becomes the more stable of the two. 

The metallic elements in Group 3A also form many molecular compounds. For example, aluminum reacts with hydrogen to form AIH3, which has properties similar to those of BeH2. The progression of properties across the second row of the periodic table illustrates the gradual shift from metallic to nonmetallic character in the main group elements. 

The Group 4A elements form compounds in both the +2 and +4 oxidation states. For carbon and silicon, the +4 oxidation state is the more stable one. For example, CO2 is more stable than CO, and Si02 is a stable compound, but SiO does not exist under ordinary conditions. As we move down the group, however, the relative stability of the two oxidation states is reversed. In tin compounds the +4 oxidation state is only slightly more stable than the +2 oxidation state. In lead compounds the +2 oxidation state is the more stable one. The outer electron configuration of lead is 6s 6p, and lead tends to lose only the 6p electrons to fonn Pb rather than both the 6p and 6x electrons to form Pb .  

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The heterocyclic complexes incorporating other main group element atoms have been prepared via the reaction of RBiBr2 with an appropriate difunctional salt or chelating ligand (see equations 7 and 8). The compound (21) is reported to have anticoccidial and insecticidal properties, as do other RBi(SR)2 compounds. 

The main-group elements are sometimes called the representative elements because they have a wide range of properties. At room temperature and atmospheric pressure, many are solids, while others are liquids or gases. About half of the main-group elements are metals. Many are extremely reactive, while several are nonreactive. The main-group elements silicon and oxygen account for four of every five atoms found on or near Earth s surface. 

Many transition metal complexes bearing dithiocarboxylato ligands have been studied from various points of view. Their coordination modes depend on the metals and the other ligands on the metals. The complexes sometimes show interesting properties, such as electron conductivity. Synthetic methods are usually as same as those of the main-group-element complexes bearing dithiocarboxylato ligands. The insertion of carbon disulfide into the metal-carbon bond is especially used in the synthesis of transition metal complexes. 

The outermost electrons of an atom are called valence electrons, which are the ones involved in the formation of chemical bonds between atoms. The similarity of the valence electron configurations (i.e., they have the same number and type of valence electrons) is what makes the elements in the same group resemble one another chemically. This observation holds true for the other main group elements as well. For instance, the halogens (Group 7A) all have outer electron configurations of n np, and they have similar properties. 

The main usefulness of Eh-pH diagrams consists in the immediacy of qualitative information about the effects of redox and acid-base properties of the system on elemental solubility. Concerning, for instance, cerium, figure 8.20 immediately shows that, within the stability field of water, delimited upward by oxidation boundary curve o and downward by reduction boundary curve r, the element (in the absence of other anionic ligands besides OH groups) is present in solution mainly as trivalent cerium Ce and as soluble tetravalent hydroxide Ce(OH)2. It is also evident that, with increasing pH, cerium precipitates as trivalent hydroxide Ce(OH)3. 

While elements within the / V I same group tend to have similar chemical properties, due to its small size the first member of each main group exhibits a chemistry that differs most from the other members of the group. 

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