Nonmetallic elements electronegativity

Two types of chemical bonds, ionic and covalent, are found in chemical compounds. An ionic bond results from the transfer of valence electrons from the atom of an electropositive element (M) to the atom(s) of an electronegative element (X). It is due to coulombic (electrostatic) attraction between the oppositely charged ions, M (cation) and X (anion). Such ionic bonds are typical of the stable salts formed by combination of the metallic elements (Na, K, Li, Mg, etc.) with the nonmetallic elements (F, Cl, Br, etc.). As an example, the formation of the magnesium chloride molecule from its elemental atoms is shown by the following sequence ... 

Table 16.4 Pauling Electronegativity A for Some Nonmetallic Elements...

The chemical elements provide examples of three of the four classes of crystalline solids described in this section. Only ionic solids are excluded, because a single element cannot have the two types of atoms of different electronegativities needed to form an ionic material. We have already discussed some of the structures formed by metallic elements, which are sufficiently electropositive that their atoms readily give up electrons to form the electron sea of metallic bonding. The nonmetallic elements are more complex in their structures, reflecting a competition between intermolecular and intramolecular bonding and producing molecular or covalent solids with varied properties. 

Electronegativity is a measure of the ability of an atom to attract electrons in a chemical bond. Metallic elements have low electronegativities and nonmetallic elements have high electronegativities. Examples of electronegativities for the first few rows of the periodic table are shown in the figure below. 

Similar logic allows us to predict which atom in an ionic bond forms the positive cation and which forms the negative anion. In an ionic bond between monatomic ions. Objective 22c the nonmetallic element has the higher electronegativity and forms the anion, and the metallic element has the lower electronegativity and forms the cation. 

Atoms of elements with widely different electronegativities tend to form ionic bonds (such as those that exist in NaCl and CaO compounds) with each other since the atom of the less electronegative element gives up its electron(s) to the atom of the more electronegative element. An ionic bond generally joins an atom of a metallic element and an atom of a nonmetallic element. Atoms of elements with comparable electronegativities tend to form polar covalent bonds with each other because the shift in... 

In a covalent bond both atoms attract electrons and share electrons between them. A metallic bond is favored between metals. In a metallic bond, atoms lose electrons to a matrix of free electrons surrounding them. Many bonds have some characteristics of more than one of the above basic bond types. Electronegativity and the location of metallic and nonmetallic elements on the periodic table are described in Skill 1.1c and 12.11. 

Standard heat of formation per bond of hydrides (g) of nonmetallic elements, compared with values calculated by the electronegativity equation. 

Most of the glasses encountered in the laboratory or in daily life are composed of mixed oxides of several elements. The oxides are usually described as the polyanion of a nonmetallic element of high electronegativity (borate, silicate. 

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