Symbols, Lewis dot

Electrons in the outermost occupied shell of any atom may play a significant role in that atoms chemical properties, including its ability to form chemical bonds. To indicate their importance, these electrons are called valence electrons (from the Latin valentia, strength ), and the shell they occupy is called the valence shell. Valence electrons can be conveniently represented as a series of dots surrounding an atomic symbol. This notation is called an electron-dot structure or, sometimes, a Lewis dot symbol, in honor of the American chemist G. N. Lewis, who first proposed the concepts of shells and valence electrons. Figure 6.2 shows the electron-dot structures for the atoms important in our discussions of ionic and covalent bonds. (Atoms of elements in groups 3 through 12 form metallic bonds, which we ll study in Chapter 18.)... 

The American chemist G. N. Lewis introduced a useful model that describes the electronic structure of the atom and provides a starting point for describing chemical bonds. The Lewis model represents the valence electrons as dots arranged around the chemical symbol for the atom the core electrons are not shown. The first four dots are displayed singly around the four sides of the elemental symbol. If the atom has more than four valence electrons, their dots are then paired with those already present. The result is a Lewis dot symbol for that atom. The Lewis notation for the elements of the first two periods is... 

For each of the following elements, tell how many electrons are in each energy level and then write the Lewis dot symbol for each atom. 

FIGURE 9.1 Lewis dot symbols for the representative elements and the noble gases. The number of unpaired dots corresponds to the number of bonds an atom of the element can form in a compound. 

In the following example, we apply the Lewis dot symbols to study the formation of an ionic compound. 

Use Lewis dot symbols to show the formation of aluminum oxide (AI2O3). 

Answer We use the electroneudality as our guide in writing formulas for ionic compounds. According to Figure 9.1, the Lewis dot symbols of A1 and O are... 

Let ns consider the Lewis strncture of the water molecule. Figure 9.1 shows the Lewis dot symbol for oxygen with two unpaired dots or two unpaired electrons, as we expect that O might form two covalent bonds. Since hydrogen has only one electron, it can form only one covalent bond. Thus the Lewis strncture for water is... 

A Lewis dot symbol shows the number of valence electrons possessed by an atom of a given element. Lewis dot symbols are useful mainly for the representative elements. 

Ionic bond, p. 330 Lattice energy, p. 333 Lewis dot symbol, p. 330 Lewis structure, p. 338 Lone pair, p. 338 Multiple bond, p. 339... 

QUESTIONS AND PROBLEMS LEWIS DOT SYMBOLS Review Questions... 

What is a Lewis dot symbol To what elements does the symbol mainly apply ... 

Write the Lewis dot symbols of the reactants and products in the following reactions. (First balance the equations.)... 

What is the difference between a Lewis dot symbol and a Lewis stmcture ... 

Lewis dot symbol. The symbol of an element with one or more dots that represent the number of valence electrons in an atom of the element. (9.1)... 

Lewis dot symbols for representative elements. Each unpaired electron is a potential bond. 

Lewis dot symbols will be used extensively in Chapter 5 in the discussions of bonding. 

Lewis dot symbol A representation of a molecule, ion, or formula unit by atomic symbols with the valence electrons shown as dots... 

Lewis dot symbols of atoms help explain the valence of elements. The orignal definition of valence was derived from the number of chemical bonds that an element would form. Counting unpaired electrons In the Lewis symbol provides the valence of elements in the s and p blocks of the periodic table. 

Because elements in the same group have the same number of valence electrons, the Lewis symbols for subsequent periods are the same, except for the identity of the elements. For example, the Lewis dot symbols for carbon, silicon, and germanium are as follows ... 

Draw the Lewis dot symbol for each of the following atoms, (a) boron, (b) fluorine, (c) selenium, (d) indium... 

Theoretical models for the strucmre of atomic nuclei predict the existence of superheavy elements that have not yet been discovered and suggest that such elements might be fairly stable if they could be produced. So researchers are currently trying to synthesize these superheavy elements to test these theories. Suppose that element 117 has been synthesized and given the atomic symbol Lt. What would the Lewis dot symbol be for this new element ... 

Use Lewis dot symbols to explain why chlorine bonds with only one hydrogen atom. 

Lewis dot symbol (7.3) Visual representation of the valence electrons of an atom. 

Our study of chemical bonds begins with an introduction to Lewis dot symbols, which shows the valence electrons on an atom. (9.1)... 

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