As has been seen earlier multiple bonding is a feature of both oxygen and nitrogen chemistry, each of which has more than one unpaired electron. We will also see that multiple bonding is a feature of carbon chemistry.
Multiple bonds involve overlap of electron clouds of a particular shape on adjacent atoms, and the overlap is better (bonds are stronger) if the atoms are smaller. Carbon, oxygen and nitrogen are small atoms from the second row of the periodic table; therefore one or more of these atoms is involved in the vast majority of multiple bonds.
The heavier atoms from the second, third and fourth row of the periodic table do not form multiple bonds to one another. Therefore for all unpaired electrons on each atom in these elements to be shared in their elemental form, more than two atoms must be present in the molecule.
In forming these molecules unpaired electrons on the atom become paired by sharing unpaired electrons on other atoms in bonds. The non-bonding electron pairs on the atoms are also non-bonding electron pairs in the molecule.
THEREFORE
The number of bonds to each atom in these molecules (P4 and S8) can be predicted from the number of unpaired valence electrons on the atom.
The number of non-bonding electron pairs on each atom in these molecules (P4 and S8) can be predicted from the number of non-bonding valence electrons on the atom.
Multiple bonds involve overlap of electron clouds of a particular shape on adjacent atoms, and the overlap is better (bonds are stronger) if the atoms are smaller. Carbon, oxygen and nitrogen are small atoms from the second row of the periodic table; therefore one or more of these atoms is involved in the vast majority of multiple bonds.
The heavier atoms from the second, third and fourth row of the periodic table do not form multiple bonds to one another. Therefore for all unpaired electrons on each atom in these elements to be shared in their elemental form, more than two atoms must be present in the molecule.
Elemental phosphorus exists as P4.
Element sulfur exists as S8.
Element sulfur exists as S8.
In forming these molecules unpaired electrons on the atom become paired by sharing unpaired electrons on other atoms in bonds. The non-bonding electron pairs on the atoms are also non-bonding electron pairs in the molecule.
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THEREFORE
The number of bonds to each atom in these molecules (P4 and S8) can be predicted from the number of unpaired valence electrons on the atom.
The number of non-bonding electron pairs on each atom in these molecules (P4 and S8) can be predicted from the number of non-bonding valence electrons on the atom.