Covalent and Ionic Bonds

Everything that you see in nature is a compound or an element. All these compounds form different types of bonds to maintain stability. Bond formation is one of the core foundations of chemistry. A chemical bond is formed by the sharing of electrons or attraction between atoms or molecules having opposing charges. There are various types of chemical bonds of which ionic and covalent bonds are the basics that one needs to know before getting into the complexities of chemistry. The physical properties of matter depend on the types of bonds formed. So let's see what these bonds are.

What is a Covalent Bond?
This bond is formed between two atoms by sharing their valence electrons. Valence electrons are those present in the outermost orbital of an atom and those which are available for sharing. When the atoms share these electrons they form a stable structure or compound. This type of bonding is seen between non-metals, as these non metals consist of valence electrons required for a covalent bond to form molecular compounds.
The nucleus of an atom consist of a positive charge known as protons. Due to the opposing charges the electrons are attracted towards the nucleus. The electrons shared in a bond are attracted to the nucleus of both atoms in the bond. There are two types of covalent bonds,

• Polar covalent bonds in which there is an equal sharing of electrons between atoms. This is mostly seen when the atoms are the same such as nitrogen-nitrogen covalent bond.
• Non polar covalent bonds are those in which there is unequal sharing of electrons due to the different non-metals participating in bond formation. This is seen due to the electronegative charge difference between atoms.

What is an Ionic Bond?
This bond is formed due electrostatic attraction between two ions, hence the name ionic bonding. A particle that is electrically charged carrying a positive or negative charge is an ion. An ionic bond is formed between a metal and a non metal. The best example for this is NaCl or common salt. Na or sodium is a positive ion and donates an electron to Cl or chlorine that is a negative ion that accepts this electron and thus forming a molecule of NaCl.

It is important to remember that stability of a molecule depends on its energy. Two atoms or ions will form a bond only when it reaches a lower energy state after bond formation than its free form.

Characteristics of Covalent and Ionic Bonds
Different physical characteristics of these bonds are given below.

Physical Properties	Covalent Bonds	Ionic Bonds
Boiling and Melting Points	Variable (lower than ionic)	High
Electrical Conductivity	None	Solids do not conduct electricity Liquids-conduct electricity
Solubility in water	Low	Higher than covalent compounds

It is important to note that both these bonds require a high energy to break them.

Ionic Bond vs Covalent Bond
Now that we have a basic idea of what these bonds are, let us compare ionic compounds vs. molecular compounds. We have already seen the difference in physical properties of the two bonds. Apart from these there are only a few other differences that we need to bear in mind.

• Covalent bonds are formed by sharing of electrons between atoms. Ionic bonds on the other hand are formed between electrostatic ions.
• Covalent bonds are formed between non-metals whereas ionic bonds are formed between a metal and a non-metal.
• The last point of difference is the state of the compounds at room temperature. Covalent compounds are liquid or gaseous at room temperature. Ionic compounds are solid at room temperature.

This was an introduction to these bonds, if you are thinking of studying chemistry as your majors, you need to delve in deeper!