And octet rule

A more elaborate example than those shown above is the anionic compound SiFg2- (Figure 1.2), which adopts a classical octahedral shape that we will meet also in many metal complexes. Silicon lies below carbon in the Periodic Table, and there are some limited similarities in their chemistry. However, the simple valence bond theory and octet rule that... 

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

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. ... 

Sason Being playful did not hurt any teacher. I was seeking one term that can replace the duet and octet rules, and I came up with the nirvana rule the profound peace of mind of the atom. The nirvana rule enables me to construct in a single stretch H2, H2O, H2O2, NH3, CH4, N2, P4, CO2, etc. 

As depicted in Figure 2.1 and outlined in the Summary of Chapter 2, viable bonding theories started to emerge from the quantum-mechanical model of the atom in the 1920s. G. N. Lewis proposed his now familiar electron-dot diagrams and octet rule for simple compounds in the early 1920s, and by the end of the decade, Nevil Sidgwick applied these ideas to coordination compounds. It was he who first proposed the idea of the coordinate-covalent bond referred to in earlier chapters. 

Structure of the atomic shell Electrostatics and frictional electricity Structure of the atomic shell Shell occupation and octet rule Electron configuration of difTcrent atoms Ionisation energy and investigating the shell... 

Figure 2-19. The BE-matriK of ethanal allows one to determine tine number of valence electrons (the sum of each row) on the atoms and to validate the octet rule,...

Protonated methane (CH ) does not violate the octet rule of carbon. A bonding electron pair (responsible for covalent bonding between C and H atoms) is forced into sharing with the proton, resulting in 2 electron-3 center bonding (2e-3c) (see Chapter 10). Higher alkanes are protonated similarly. 

Lewis s concept of shared electron parr bonds allows for four electron double bonds and SIX electron triple bonds Carbon dioxide (CO2) has two carbon-oxygen double bonds and the octet rule is satisfied for both carbon and oxygen Similarly the most stable Lewis structure for hydrogen cyanide (HCN) has a carbon-nitrogen triple bond... 

Multiple bonds are very common m organic chemistry Ethylene (C2H4) contains a carbon-carbon double bond m its most stable Lewis structure and each carbon has a completed octet The most stable Lewis structure for acetylene (C2H2) contains a carbon-carbon triple bond Here again the octet rule is satisfied... 

Lewis structures in which second row elements own or share more than eight valence electrons are especially unstable and make no contribution to the true structure (The octet rule may be ex ceeded for elements beyond the second row)... 

The two Lewis structures D and E of methyl nitrite satisfy the octet rule... 

Among structural formulas in which the octet rule IS satisfied for all atoms and one or more of these atoms bears a formal charge the most stable reso nance form is the one in which negative charge re sides on the most electronegative atom... 

Of the two resonance forms A and B A has only six electrons around its positively charged carbon B satisfies the octet rule for both carbon and oxygen It is more stable than A and more stable than a carbocation formed by protonation of a typical alkene... 

Many transition metal complexes including Ni(CO)4 obey the 18 electron rule, which IS to transition metal complexes as the octet rule is to mam group elements like carbon and oxygen It states that... 

Isomtriles are stable often naturally occumng compounds that contain a divalent carbon An example is axisonitnle 3 which can be isolated from a species of sponge and possesses anti malanal activity Write a resonance form for axisonitnle 3 that satisfies the octet rule Don t for get to include formal charges... 

Lewis structure (Section 1 3) A chemical formula in which electrons are represented by dots Two dots (or a line) be tween two atoms represent a covalent bond in a Lewis structure Unshared electrons are explicitly shown and sta ble Lewis structures are those in which the octet rule is sat isfied... 

Octet rule (Section 1 3) When forming compounds atoms gain lose or share electrons so that the number of their va lence electrons is the same as that of the nearest noble gas For the elements carbon nitrogen oxygen and the halo gens this number is 8... 

Note that these compounds are covalently bonded compounds containing only hydrogen and carbon. The differences in their strucmral formulas are apparent the alkanes have only single bonds in their structural formulas, while the alkenes have one (and only one) double bond in their structural formulas. There are different numbers of hydrogen atoms in the two analogous series. This difference is due to the octet rule that carbon must satisfy. Since one pair of carbon atoms shares a double bond, this fact reduces the number of electrons the carbons need (collectively) by two, so there are two fewer hydrogen atoms in the alkene than in the corresponding alkane. 

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