Carbon octet rule followed

Rule 4 Resonance forms obey norma] rules of valency. A resonance form is like any other structure the octet rule still applies to main-group atoms. For example, one of the following structures for the acetate ion is not a valid resonance form because the carbon atom has five bonds and ten valence electrons ... 

Each carbon atom forms a total of four covalent bonds. This is illustrated by the struc- Carbon always follows the octet rule in... 

The octet rule accounts for the valences of many of the elements and the structures of many compounds. Carbon, nitrogen, oxygen, and fluorine obey the octet rule rigorously, provided there are enough electrons to go around. However, some compounds have an odd number of electrons. In addition, an atom of phosphorus, sulfur, chlorine, or another nonmetal in Period 3 and subsequent periods can accommodate more than eight electrons in its valence shell. The following two sections show how to recognize exceptions to the octet rule. 

A major fragmentation pathway in aldehydes and ketones is cleavage of the bonds to the carbonyl carbon. This process is similar to the fragmentation that occurs with alcohols and produces cations that are relatively stable because the octet rule is satisfied at all of the atoms. The major peaks at m/z 85 and m/z 43 in the spectrum of 4-methyl-2-pentanone (see Figure 15.13) result from this cleavage, as illustrated in the following equations ... 

Write Lewis structures that obey the octet rule for each of the following. Except for HCN and H2CO, the first atom listed is. the central atom. For HCN and H2CO, carbon is the central atom. 

In the second mechanism, the leaving group departs simultaneously with the incoming nucleophile approaching. Thus, at any one time the central carbon atom sees only eight electrons, and so does not violate the Octet rule. This mechanism is called bimolecular substitution, and may be represented in the following manner. 

Our first example is tetrafluoromethane, CF4. The total number of available (outershell) electrons (32) is given by the carbon contribution of four electrons and the contribution of seven electrons from each fluorine atom. The structure we draw follows the octet rule (recall that the line represents two electrons in a bond) ... 

You should practice writing many Lewis formulas. A few common types of organic compounds and their Lewis formulas are shown here. Each follows the octet rule. Methane, CH4, is the simplest of a huge family of organic compounds called hydrocarbons (composed solely of hydrogen and carbon). Ethane, is another hydrocarbon that contains only... 

The second-row nonmetals carbon through fluorine form stable molecules when they are surrounded by enough electrons to fill the valence orbitals—that is, the one 2s and the three 2p orbitals. Eight electrons are required to fill these orbitals, so these elements typically obey the octet rule they are surrounded by eight electrons. An example is the F2 molecule, which has the following Lewis structure ... 

Write Lewis structures that obey the octet rule (duet rule for H) for each of the following molecules. Carbon Is the central atom In CH4, nitrogen Is the central atom In NH3, and oxygen Is the... 

The compounds containing the elements carbon, nitrogen, oxygen, and fluorine are accurately described by Lewis structures in the vast majority of cases. However, there are a few exceptions. One important example is the oxygen molecule, O2. The following Lewis structure that satisfies the octet rule can be drawn for O2 (see Self-Check Exercise 12.4). 

The sum of the shared (bonding) electrons and the lone pair electrons for carbon, nitrogen, oxygen, and fluorine atoms must be eight—an octet. Usually the other elements in groups IV, V, VI, and VII also follow the octet rule. 

The partial Lewis structure that follows is for a hydrocarbon molecule. In the full Lewis structure, each carbon atom satisfies the octet rule, and there are no unshared electron pairs in the molecule. The carbon-carbon bonds are labeled 1, 2, and 3. (a) Determine where the hydrogen atoms are in the molecule. (b) Rank the carbon-carbon bonds in order of increasing bond length, (c) Rank the carbon-carbon bonds in order of increasing bond enthalpy. [Sections 8.3 and 8.8]... 

All of the hydrogens are bonded to carbon in both of the following. Write a Lewis structure that satisfies the octet rule for each. 

You may use the procedure that follows to sketch the Lewis diagram for any species that obeys the octet rule. Each step is illustrated by drawing the Lewis diagram for carbon tetrachloride, CCI4. 

The number of covalent bonds formed by an atom is termed its COVALENCY. The covalency of an atom is equal to the number of electrons the atom needs to become isoelectronic with a noble gas. Some of the more common elements have the following covalencies when they follow the octet rule and also have no charge hydrogen and the halogens, 1 oxygen and sulfur, 2 nitrogen and phosphorus, 3 carbon and silicon, 4. LEWIS ELECTRONIC FORMULAS, in which bonds and unshared electrons are shown, are given for a few typical compounds of these elements ... 

These elements (E) have four valence electrons and are tetravalent as carbon below which they are located. The compounds ER4 thus follow the octet rule which confers them a great stability. The tetraalkyl-element complexes are almost apolar and particularly robust and inert. However, the energy of the E-C bond decreases upon going down in the column of the periodic table. Thus, the tetraalkyllead complexes are less robust towards thermolysis than the lighter analogs. They decompose between 100 and 200°C, which was eventually applied to provide their antiknock properties. The chemistry of these elements is largely dominated by the oxidation state and coordination number 4, but the oxidation state and coordination number 2 is also known for all, and its stability increases upon going down in the column of the periodic table. 

Molecules that form only two single bonds, with no lone pairs, are rare because they do not follow the octet rule. However, the same geometry is observed in all molecules that have two electron groups (and no lone pairs). Consider the Lewis structure of CO2, which has two electron groups (the double bonds) around the central carbon atom ... 

Carbon always follows the octet rule in stable compounds. 

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