Nonmetals group

The heavier elements in the same group (15) as nitrogen are occasionally known as pnictogens and their compounds with metals as pnictides . Although the elements form some compounds similar to those of nitrogen, there are very pronounced differences, as is found in other nonmetal groups (see Topics FI and F5). 

The elements known collectively as the chalcogens are in the same group (16) as oxygen (Topic F7). They form some compounds similar to those of oxygen, but show many differences characteristic of other nonmetal groups (see Topic FI). 

Components That Occupy Metal Nonmetal Group 8A Discrete molecules Ions... 

The chemistry exhibited by the first member of a nonmetal group can differ from that of subsequent members. For example, nonmetals in period 3 and below can accommodate a larger number of bonded neighbors. (Section 8.7) Another important difference is that the first element in any group can more readily form tt bonds. This trend is due, in part, to size because small atoms are able to approach each other more closely. As a result, the overlap of p orbitals, which results in the formation of tt bonds, is more effective for the first element in each group (T FIGURE 22.2). More effective overlap means stronger tt bonds, reflected in bond enthalpies. (Section 8.8) For example, the difference between the enthalpies of the C—C bond and the C=C bond is about 270 kj/mol ... 

The chemistry exhibited by the first member of a nonmetal group can differ from that of subsequent members in important ways. Two differences are particularly notable (1) The first member is able to accommodate fewer bonded neighbors, cco (Section 8.7) For example, nitrogen is able to bond to a maximum of three Cl J atoms, NCI3, whereas phosphorus can bond to five, PCI5. The small... 

The most electronegative elements are the nonmetals (Groups 5A-7A) and the least electronegative elements are the alkali and alkaline earth metals (Groups 1A-2A) and aluminum. Beryllium, the first member of Group 2A, forms mostly covalent compounds. 

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