Duet of electrons

These examples illustrate the principle that atoms in covalently bonded species tend to have noble-gas electronic structures. This generalization is often referred to as the octet rule. Nonmetals, except for hydrogen, achieve a noble-gas structure by sharing in an octet of electrons (eight). Hydrogen atoms, in molecules or polyatomic ions, are surrounded by a duet of electrons (two). 

In these examples, it can be seen that the carbon and chlorine atoms can achieve octets of electrons by sharing pairs of electrons with other atoms. Hydrogen atoms attain duets of electrons because the first shell is complete when it contains two electrons. We note from Sec. 5.4 that main group cations generally lose all their valence electrons, and then have none left in their valence shell. 

An atom is electron-deficient if it lacks an octet of electrons in its valence shell (or, for H, a duet of electrons). 

Hydrogen atoms attain duets of electrons because the first shell is complete when it contains two electrons. 

Add the remainder of the available electrons to complete the octets (or duets) of all the atoms. There should be just enough if the molecule or ion follows the octet rule. 

It must be emphasized that the octet rule does not describe the electron configuration of all compounds. The very existence of any compounds of the noble gases is evidence that the octet rule does not apply in all cases. Other examples of compounds that do not obey the octet rule are BF,. PF5, and SF6. But the octet rule does summarize, systematize, and explain the bonding in so many compounds that it is well worth learning and understanding. Compounds in which atoms attain the configuration of helium (the duet) are considered to obey the octet rule, despite the fact that they achieve only the duet characteristic of the complete first shell of electrons. 

In the Lewis structure for C2FL, each carbon atom shares four pairs of electrons with three hydrogen atoms and the other carbon atom. With this arrangement, the carbon atoms complete their octets while the hydrogen atoms complete their duets. 

Hydrogen never has an octet of electrons in any of its compounds, but rather a pair (or duet, if you prefer). An example is the Lewis structure of H20 (below). In many compounds in which the central atom is from the second period or higher, there are more than eight electrons around the central atom an example of a compound with such an expanded octet is IC13 (below). Finally, in some compounds, there are less than eight electrons around the central atom one such electron deficient compound is BF3. 

Because the maximum number of electrons in the first shell of an atom is 2, helium is stable with 2 electrons in its only occupied shell. The other very light elements—hydrogen, lithium, and beryllium—tend to form stable states by achieving the 2-electron configuration of helium. Having 2 electrons in the first shell, when that is the only shell and therefore the outermost shell, is a stable state, and the 2 electrons are sometimes called a duet. When there is only one shell, 2 electrons in that shell act like 8 electrons in any other outermost shell. Therefore, an atom with 2 electrons in its outermost first shell is often said to obey the octet rule, although duet rule would be more precise. 

Electrons shared between hydrogen atoms are counted toward the duets of both atoms. In the hydrogen molecule, each hydrogen atom has a total of two electrons in its first shell and, thus, a stable configuration. Electrons shared between other nonmetal atoms are counted toward the octets of both. 

Explain tbe "duet" and "octet" rules and bow they are used to describe the arrangement of electrons in a molecule. 

The noble gases have a complete outer shell of electrons two in helium and eight in the rest an octet is eight electrons in the outer shell a duet is two electrons in the outer shell. Both the octet and duet are stable configurations of electrons in an atom. It is because of the complete outer shell of electrons that the noble gases do not react chemically. All of the other elements on the Periodic Table try to reach the same stable electron arrangement as the nearest noble gas, which is usually in the same period. That is why there are chemical reactions the elements are trying to reach stability. 

Atomic Number=Niimber of Protons Atomic Weight "Protons 4 Neutrons Number of Protons Number of Electrons Octei-8 electrons outer shell Duet 2 electrons outer shell... 

Do the two stmctmes have the same nimiber of electrons Is the octet mle satisfied for all atoms other than hydrogen, wliich should have a duet of elections ... 

In writing Lewis structures for molecules, what is meant by the duet rule To which element does the duet rule apply What do we mean by the octet rule Why is attaining an octet of electrons important for an atom when it forms bonds to other atoms What is a bonding pair of electrons What is a nonbonding (or lone) pair of electrons ... 

In order to use only a single term to describe this attainment of electronic satisfaction, we can call the Duet and Octet Rules the Law of Nirvana —Nirvana in the case of the atom would mean for us reaching the state of no more need to bind. Thus, by attaining duet (for the first period) or octet (for all other periods), the atom reaches Nirvana. ... 

The shared electrons—those that appear in the space between the two atoms— count toward the octets (or duets) of both of the atoms. 

Since the nitrogen atom has an octet and since all of the hydrogen atoms have duets, the placement of electrons is complete. Write the entire Lewis structure in brackets indicating the charge of the ion in the upper right corner. 

Atoms with eight valence electrons are particularly stable and are said to have an octet. Atoms such as hydrogen, helium, lithium, and beryllium are exceptions to the octet rule as they achieve stability when their outermost shell contains two electrons—a duet. A chemical bond is the sharing or transfer of electrons to attain stable electron configurations among the bonding atoms. 

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