Monatomic ions compounds formed from

Compounds Formed from Monatomic Ions Let s first consider how to name binary ionic compounds, those composed of ions of two elements. 

Ionic compounds form when a metal transfers electrons to a nonmetal, and the resulting positive and negative ions attract each other to form a three-dimensional array. In many cases, metal atoms lose and nonmetal atoms gain enough electrons to attain the same number of electrons as in atoms of the nearest noble gas. Covalent compounds form when elements, usually nonmetals, share electrons. Each covalent bond is an electron pair mutually attracted by two atomic nuclei. Monatomic ions are derived from single atoms. Polyatomic ions consist of two or more covalently bonded atoms that have a net positive or negative charge due to a deficit or excess of electrons. 

One factor that favors an atom of a representative element forming a monatomic ion in a compound is the formation of a stable noble gas electron configuration. Energy considerations are consistent with this observation. For example, as one mole of Li from Group LA forms one mole of Li+ ions, it absorbs 520 kj per mole of Li atoms. The IE2 value is 14 times greater, 7298 kj/mol, and is prohibitively large for the formation of Li + ions under ordinary conditions. For LE+ ions to form, an electron would have to be removed from the filled first shell. We recognize that this is unlikely. The other alkali metals behave in the same way, for similar reasons. 

A binary Ionic compound is one composed of ions from only two elements, one a metal, the other a nonmetal. NaCl, CaF2, and FeCl3 are all binary ionic compounds. Before starting to develop formulas for ionic compounds, it is necessary to know the monatomic ions (ions formed from a single atom) of the common metals and nonmetals. 

The central idea of the ionic bonding model is the transfer of electrons from meted atoms to nonmetal atoms to form ions that come together in a solid ionic compound. For nearly every monatomic ion of a main-group element, the electron configuration has a filled outer level either two or eight electrons, the same number as in the nearest noble gas (octet rule). 

If energy is required to form monatomic ions from metals and nonmetals, why do ionic compounds exist ... 

Use condensed electron configurations and Lewis electron-dot symbols to depict the monatomic ions formed from each of the following atoms, and predict the formula of the compound the ions produce ... 

In effect, the metal atoms transfer electrons to the nonmetal atoms. The resulting large numbers of cations and anions attract each other and form the ionic compound. A cation or anion derived from a single atom is called a monatomic ion we ll discuss polyatomic ions, those derived from a small group of atoms, later. 

Explain the essential features of ionic and covalent compounds and distinguish between them predict the monatomic ion formed from a main-group element ( 2.7) (SP 2.6) (EPs 2.45-2.57)... 

The charge of a monatomic ion is equal to its oxidation number. The oxidation number, or oxidation state, of an ion in an ionic compound is numerically equal to the number of electrons that were transferred to or from an atom of the element in forming the compound. If the electrons were transferred from the atom, the ion has a positive oxidation state. If they were transferred to the atom, the ion has a negative oxidation state. Most transition metals and metals of groups 3A and 4A can have more than one oxidation number. 

The name of a monatomic cation is the same as the name of the element forming it, with the addition of the word ion, as in sodium ion for Na+. When an element can form more than one kind of cation, such as Cu+ and Cu2+ from copper, we use the oxidation number, the charge of the cation, written as a Roman numeral in parentheses following the name of the element. Thus, Cu+ is a copper(I) ion and Cu2+ is a copper(II) ion. Similarly, Fe2+ is an iron(II) ion and Fe3" is an iron(III) ion. As shown in Fig. C.6, most transition metals form more than one kind of ion so unless we are given other information we need to include the oxidation number in the names of their compounds. 

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