Metals, non-metals and ions make a bond to stabilize them. For metals, there is metallic bonding. For ions, there is ionic bonding. Do you know about the bonding of non metals? In this lesson we will be learning about covalent bonding.
What is covalent bonding?
It is the bonding between 2 nonmetals. It is caused by the mutual sharing of electrons.
Explanation
For example, 2 oxygen atoms covalently bond together to form the diatomic molecule. Both oxygen atoms have 6 valence electrons. To gain the electronic configuration of noble gas, they need two more electrons. They, in mutual, share two electrons each and thus both follow the octet rule and are now covalently combined. Mutual sharing of 2 pairs of electrons is donated by two horizontal lines.
Let's have a look at another example, Chlorine exists as a diatomic molecule which is formed by covalent bonding. Chlorine has 7 valence electrons. It needs one more electron to complete its octet. 2 chlorine atoms share 1 electron each. Thus, they are covalently bonded. Mutual sharing of 1 pair of electrons is donated by one single horizontal line.
Properties of covalent compounds
They have low melting and boiling points because of less forces of attraction between them. For example, Ammonia [NH3], Water [H2O] and Oxygen [O2]. Melting point of water is 0 C and for ammonia it is -77.73°C.
They also don’t conduct electricity because all the electrons are used in bonding so they don’t have any free moving electrons to conduct electricity. Let's take a look at an example, diamond is an allotrope of carbon which is arranged in covalent structure where each carbon atom is joined to 4 carbon atoms and forming a tetrahedral structure. All the atoms of diamond are used in bonding so it does not conduct electricity.
They are insoluble in water but dissolve in organic solvent. Water molecules do not attract covalent compounds. Water is a polar substance while covalent compounds are nonpolar. Polar substances only dissolve in polar substances so they are insoluble in water. For example, one can see the bubbles of oxygen gas because water does not dissolve it.
This lesson covers the basics of covalent bonding. Comment down below whether this was useful or not.
*All pictures are taken from google*
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