Third Official Post (For Chemistry Journal)
The second type of bonding which I will be talking about is covalent bond. Covalent bond is the sharing of pairs of electrons between atoms or atoms with other covalent bonds. In other words, it is the attraction-to-repulsion stability that forms between atoms when they share electrons. As discussed in valence bond theory, covalent bond means that atoms share valence.
Through covalent bonding in the molecule H2 (the 2 is supposed to be sub-script), the hydrogen atoms share the two electrons. Covalent bonding does not require the two atoms to be from the same element but just that the two atoms are of comparable electro negativity. In contrast to “ionic bonds”, the strength of covalent bond is dependant on the angular relation between atoms in polyatomic molecules.
The number of pairs of electrons shared between atoms forming a covalent bond is indicated by the bond order.
Ø Single bond- Most common and indicates the sharing of only a pair of electrons between two atoms. Usually has a sigma bond
Ø Double bond- Typically has a sigma bond and a pi bond, where two lobes of one involved electron orbital overlap two lobes of the other involved electron orbital.
Ø Triple bond- Usually has a sigma bond and two pi bonds
Ø Quadruple bond- Found in transition metals like molybdenum
Ø Quintuple bond- Found to exist in some dichromium (a chemical) compounds
Ø Sextuple bond- Found in diatomic tungsten and molybdenum
The above covalent bonds are actually powerful and pervasive. In my next entry, I will be talking about ionic bonding.
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