In Chemistry, you have definitely heard the word ‘compounds.’ But have you actually wondered what it is? When two or more elements come together and combined, the compound gets formed.
Compounds are of two kinds: Ionic and Molecular.
Ionic Compounds vs Molecular Compounds
The difference between Ionic and Molecular Compounds is that the electrons of atoms in ionic compounds are transferred between the elements because of the presence of a difference in electronegativity. However, in the case of molecular compounds, the electrons are only shared but not transferred.
To understand the difference better, you need to have a good understanding of the basic terminology. Two or more than two atoms of different elements combine to form a molecule, which is the basic unit of a compound.
Every compound is different in terms of properties. This is due to the fact that every element that a compound consists of possesses different properties. Electronegativity is also one of the most important terms to know.
Electronegativity is the tendency of an atom of an element to attract the electrons of other elements towards its core. A compound may be polar or non-polar, and this entirely depends on the electronegativity of the elements.
Comparison Table Between Ionic Compounds and Molecular Compounds (in Tabular Form)
|Parameter of Comparison||Ionic Compound||Molecular Compound|
|Definition||In ionic compounds, the electrons of atoms are transferred due to the presence of electronegativity difference.||Here, the electrons of atoms are only shared between the elements rather than getting transferred.|
|Type of Elements||This is formed between one metal and a non-metal element.||This is mainly formed between two non-metals.|
|Nature||They are solid in nature.||They generally exist in the form of gases or liquids.|
|Melting Points||Ionic compounds have a high melting point, i.e., above 300° C.||Molecular compounds have a low melting point. The bond between the atoms breaks on heating them.|
|Solubility||They get broken down into ions when dissolved in water.||Only the compounds with O, N, and F atoms are soluble in water.|
What are Ionic Compounds?
Every atom is comprised of a number of protons, neutrons, and electrons. It is generally seen that the number of protons and electrons inside of an atom is the same. However, sometimes the count of the electrons differs from that of protons.
This is when we get an ion. An ion is formed when electrons are gained or loosen by an atom. This is what creates a charge on the atom. This charge could either be negative or positive.
The attraction between these two opposite charges is known as an ionic bond, which in result forms an ionic compound.
Atoms that possess a negative charge due to the gain of electrons are known as anions whereas, atoms having a positive charge on them because of losing electrons are called cations.
An example of the ionic compound is table salt, which has a chemical formula NaCl. In the case of NaCl, the atom of the sodium loses an electron, whereas the chlorine atom gains an electron. Together they both form an ionic bond resulting in the formation of an ionic compound.
The type of structure formed by ionic compounds is usually of lattice shape. Ionic bonds are known to be very strong. They also have a high melting and boiling point.
What are Molecular Compounds?
Most people confuse molecular or covalent compounds with ionic compounds. However, both of them are very different in all aspects.
In a molecular compound, the electrons are shared by the atoms of an element in order to form a compound. Unlike ionic compounds, electrons are not either gained or lost by an atom here.
The attraction that occurs between the atoms of molecules is known as a covalent bond. The conductivity of electricity in a molecular compound is often very little or not at all.
A covalent bond is usually formed between two elements, which are non-metallic in nature. The boiling, as well as the melting points of molecular compounds, is very low as compared to ionic compounds.
Molecular compounds can ameliorate the flow of electricity in special conditions like in the polar and aqueous state. A molecule is considered to be the most basic unit of a covalent bond.
This is because whenever the covalent bond is made between the atoms, the group of atoms obtained is known to be a molecule.
Main Differences Between Ionic Compounds and Molecular Compounds
- The formation of an ionic compound is done by the transfer of electrons between the atoms of different elements. However, the formation of a molecular compound is done by the sharing of electrons between the atoms of two or more than two separate elements.
- An ionic bond is formed between one metallic and one non-metallic element. However, for a molecular bond to create, two or more than two non-metals share their electrons.
- The ionic compound breaks down into ions when dissolved in water. They are soluble in nature.
On the other hand, molecular compounds break down into molecules on dissolving. Most of them are not soluble in nature.
- The boiling and melting point of ionic compounds is very high, i.e., above 300°C. The melting and boiling point of molecular compounds is low as in comparison to ionic compounds. This remains lower than 300° C.
- Ionic compounds exist in the solid-state. However, molecular compounds remain in all three states at standard temperature and pressure.
An ionic compound is formed by the transfer of electrons of an atom to another atom, whereas for the formation of a covalent bond, the sharing of electrons between the atoms of two or more than two elements occurs.
Ionic compounds are soluble in water, and they break down into ions on dissolving. On the other hand, most of the molecular compounds are not soluble in water except for sugar and ethanol.
One atom loses an electron and gains a positive charge on it is known as an anion, whereas other gains an electron and gains a negative charge known as a cation.
Both of these atoms develop an attraction towards each other, which is known as the ionic bond.
However, in the case of the covalent bond, only the sharing of an electron occurs instead of transferring electrons.