Karnataka SSLC Karnataka Secondary Education Examination Board
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# Metals and Nonmetals - Formation and Properties of Covalent Compounds

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Covalent Bonding

As per the electronic configuration of Carbon, it needs to gain or lose 4 electrons to become stable, which seems impossible as:

• Carbon cannot gain 4 electrons to become C4-, because it will be tough for 6 protons to hold 10 electrons and so the atom will become unstable.
• Carbon cannot lose 4 electrons to become C4+ because it would require a large amount of energy to remove out 4 electrons and also the C4+ would have only 2 electrons held by proton, which will again become unstable

Carbon cannot gain or donate electrons, so to complete its nearest noble gas configuration, it shares electron to form a covalent bond.

Properties of Covalent Bond

If the normal valance of an atom is not satisfied by sharing a single electron pair between atoms, the atoms may share more than one electron pair between them. Some of the properties of covalent bonds are:

• Covalent bonding does not result in the formation of new electrons. The bond only pairs them.
• They are very powerful chemical bonds that exist between atoms.
• A covalent bond normally contains the energy of about ~80 kilocalories per mole (kcal/mol).
• Covalent bonds rarely break spontaneously after it is formed.
• Covalent bonds are directional where the atoms that are bonded showcase specific orientations relative to one another.
• Most compounds having covalent bonds exhibit relatively low melting points and boiling points.
• Compounds with covalent bonds usually have lower ethalpies of vapourization and fusion.
• Compounds formed by covalent bonding don’t conduct electricity due to the lack of free electrons.
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