Covalency vs. Electrovalency

Attribute	Covalency	Electrovalency
Bond Type	Sharing of electrons between atoms	Transfer of electrons from one atom to another
Electron Distribution	Electrons are shared between atoms	Electrons are transferred to form ions
Electronegativity	Atoms have similar electronegativity	Atoms have different electronegativity
Formation	Occurs between nonmetals	Occurs between metals and nonmetals
Bond Strength	Relatively weaker	Relatively stronger
Examples	Water (H2O), Methane (CH4)	Sodium Chloride (NaCl), Calcium Oxide (CaO)

Introduction

Chemical bonding is a fundamental concept in chemistry that describes the attractive forces between atoms, ions, or molecules. Two common types of chemical bonding are covalent bonding and electrovalent bonding, also known as ionic bonding. While both types of bonding involve the sharing or transfer of electrons, they differ in several key aspects. This article aims to explore and compare the attributes of covalency and electrovalency, shedding light on their unique characteristics and applications.

Covalency

Covalent bonding occurs when two or more atoms share electrons to achieve a stable electron configuration. In a covalent bond, the shared electrons are localized between the bonded atoms, forming a molecular orbital. This sharing of electrons allows each atom to attain a more stable state by filling their valence shells. Covalent bonds are typically formed between nonmetals or between a nonmetal and a metalloid.

One of the key attributes of covalency is the concept of electron density. In a covalent bond, the electron density is concentrated between the bonded atoms, resulting in a strong bond. This shared electron density also contributes to the strength and stability of covalent compounds. Additionally, covalent compounds tend to have lower melting and boiling points compared to ionic compounds, as the intermolecular forces between covalent molecules are generally weaker.

Covalent compounds often exhibit a wide range of physical properties, including varying degrees of solubility, electrical conductivity, and volatility. The solubility of covalent compounds depends on the nature of the compound and the solvent, as well as the presence of polar or nonpolar bonds. Covalent compounds can be classified into polar and nonpolar molecules, depending on the electronegativity difference between the bonded atoms. Polar covalent compounds have an uneven distribution of electron density, resulting in partial charges and the ability to form hydrogen bonds.

Furthermore, covalent compounds can exist in different states of matter, such as gases, liquids, or solids, depending on the strength of intermolecular forces. For example, molecular compounds like water (H2O) and methane (CH4) are gases at room temperature, while others like glucose (C6H12O6) are solids. The electrical conductivity of covalent compounds is generally low, as they lack free ions or delocalized electrons required for conducting electricity.

Electrovalency

Electrovalent bonding, also known as ionic bonding, occurs between atoms with significantly different electronegativities. In this type of bonding, one atom donates electrons to another atom, resulting in the formation of positively charged cations and negatively charged anions. The resulting electrostatic attraction between the oppositely charged ions forms an ionic bond. Electrovalent compounds are typically formed between metals and nonmetals.

One of the key attributes of electrovalency is the transfer of electrons. Unlike covalent bonds, electrovalent bonds involve the complete transfer of one or more electrons from the metal atom to the nonmetal atom. This transfer of electrons leads to the formation of ions with opposite charges, which are held together by strong electrostatic forces. The strength of the ionic bond depends on the charges of the ions and the distance between them.

Electrovalent compounds often exhibit high melting and boiling points due to the strong electrostatic forces between the ions. These compounds form a crystalline lattice structure, where each ion is surrounded by ions of the opposite charge. The lattice structure contributes to the rigidity and brittleness of ionic compounds. When an ionic compound is dissolved in water, the ions dissociate and become surrounded by water molecules, resulting in the compound's ability to conduct electricity.

Furthermore, electrovalent compounds often have distinct physical properties, such as high solubility in polar solvents and poor solubility in nonpolar solvents. The solubility of ionic compounds depends on the strength of the ionic bond and the ability of the solvent to separate the ions. Additionally, ionic compounds are often characterized by their crystal clear appearance, high hardness, and ability to form cleavage planes.

It is important to note that electrovalent compounds can also exhibit some covalent characteristics. In some cases, there may be a partial sharing of electrons between the ions, resulting in a degree of covalent character. This is particularly observed in compounds with polarizing cations or anions, where the electron cloud of one ion is distorted by the other, leading to a localized covalent bond.

Comparison

Covalency and electrovalency differ in several aspects, including the nature of bonding, electron sharing or transfer, physical properties, and solubility. Covalent bonding involves the sharing of electrons between atoms, resulting in the formation of molecular orbitals. On the other hand, electrovalent bonding involves the complete transfer of electrons, leading to the formation of oppositely charged ions.

Covalent compounds tend to have lower melting and boiling points compared to ionic compounds due to weaker intermolecular forces. In contrast, ionic compounds have high melting and boiling points due to strong electrostatic forces between ions. Covalent compounds can exist in various states of matter, while ionic compounds are typically solids at room temperature.

Regarding solubility, covalent compounds exhibit a wide range of solubilities depending on the nature of the compound and the solvent. Polar covalent compounds can form hydrogen bonds and have higher solubilities in polar solvents. In contrast, ionic compounds are highly soluble in polar solvents but have poor solubility in nonpolar solvents.

Covalent compounds generally have low electrical conductivity, as they lack free ions or delocalized electrons. In contrast, ionic compounds can conduct electricity when dissolved in water or in the molten state, as the ions are free to move and carry electric charge.

While covalent compounds often exhibit a wide range of physical properties, including volatility and electrical conductivity, ionic compounds are characterized by their crystal clear appearance, high hardness, and ability to form cleavage planes.

Conclusion

In conclusion, covalency and electrovalency are two distinct types of chemical bonding with unique attributes and applications. Covalent bonding involves the sharing of electrons between atoms, resulting in the formation of molecular orbitals. Covalent compounds exhibit a wide range of physical properties and solubilities, with lower melting and boiling points compared to ionic compounds. On the other hand, electrovalent bonding involves the complete transfer of electrons, leading to the formation of oppositely charged ions. Electrovalent compounds have high melting and boiling points, form crystalline lattice structures, and exhibit distinct physical properties. Understanding the differences between covalency and electrovalency is crucial in comprehending the behavior and properties of various chemical compounds.