Oxygen atom valence electrons

For oxygen (twelve valence electrons, six on each atom), the only Lewis structure that satisfies the octet rule is... 

The green oxygen m Figure 1 5 owns three unshared pairs (six electrons) and shares two electrons with nitrogen to give it an electron count of seven This is one more than the number of electrons m the valence shell of an oxygen atom and so its formal charge is —1... 

A neutral carbon atom has four valence electrons Five electrons are assigned to the CH2OH carbon therefore it has an oxidation number of -1 Seven electrons are assigned to the CH3 carbon therefore it has an oxidation number of-3 As expected this method gives an oxidation number of -2 for oxygen and +1 for each hydrogen... 

Octet rule (Section 1.3) When forming compounds, atoms gain, lose, or share electrons so that the number of their valence electrons is the same as that of the nearest noble gas. For the elements carbon, nitrogen, oxygen, and the halogens, this number is 8. 

This difference is due to the two lone pairs on the oxygen. Of the six valence electrons on the oxygen atom, two are involved in the double bond with the carbon, and the other four exist as two lone pairs. In Chapter 4, we ll examine the IR spectra for these two molecules. The orbitals suggest that we ll find very different frequencies for the two systems. In Chapter 9, we ll look at the transition to the first excited state in formaldehyde. ... 

The number of covalent bonds an atom forms depends on how many additional valence electrons it needs to reach a noble-gas configuration. Hydrogen has one valence electron (Is) and needs one more to reach the helium configuration (Is2), so it forms one bond. Carbon has four valence electrons (2s2 2p2) and needs four more to reach the neon configuration (2s2 2p6), so it forms four bonds. Nitrogen has five valence electrons (2s2 2p3), needs three more, and forms three bonds oxygen has six valence electrons (2s2 2p4), needs two more, and forms two bonds and the halogens have seven valence electrons, need one more, and form one bond. 

The carbon-oxygen double bond of a carbonyl group is similar in many respects to the carbon-carbon double bond of an alkene. The carbonyl carbon atom is s/ 2-hybridized and forms three valence electron remains in a carbon p orbital and forms a tt bond to oxygen by overlap with an oxygen p orbital. The oxygen atom also has two nonbonding pairs of electrons, w hich occupy its remaining two orbitals. 

Notice that in each case the oxygen or nitrogen atom is surrounded by eight valence electrons. In each species, a single electron pair is shared between two bonded atoms. These bonds are called single bonds. There is one single bond in the OH- ion, two in the H20 molecule, three in NH3, and four in NH4+. There are three unshared pairs in the hydroxide ion, two in the water molecule, one in the ammonia molecule, and none in the ammonium ion. 

The neutral oxygen atom has eight electrons. Six of these occupy the 2s, 2p orbitals and are much more easily removed than the two in the Is orbital. Therefore oxygen has six valence electrons. The 2s, 2p orbitals are the valence orbitals. They can accommodate the valence electrons in two ways, as follows ... 

For the same reason we discussed for oxygen atoms, the nitrogen atom is most stable when it has the maximum number of partially filled valence orbitals. This keeps the electrons as far apart as possible. The most stable state of the nitrogen atom is as follows ... 

We see that each oxygen atom has residual bonding capacity. Each atom could, for example, react with a hydrogen atom to form hydrogen peroxide, as shown in electron dot representation (26). Each oxygen atom could react with a fluorine atom to form F2O2. In short, each oxygen atom is in need of another atom with mi electron in a half-filled valence orbital so that it can act as a divalent atom. 

The oxygen atom, with valence electron configuration 2s12px12pv 12p J, has two electrons with unpaired spins (its Lewis symbol is -O-, which we abbreviate to -0-). Two radicals are also produced when the oxygen atom attacks a hydrogen molecule ... 

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