Electronegativity and polarity are two different but related concepts in chemistry. They describe the attraction of electrons. A clear idea about the difference between electronegativity and polarity is important for understanding chemical properties.
What is the difference between electronegativity and polarity? Electronegativity is a measure of an atom’s tendency to attract electrons towards itself when forming a chemical bond, whereas polarity is the separation of electric charge within a molecule.
Key Areas Covered
1. What is Electronegativity
– Definition, Features
2. What is Polarity
– Definition, Features
3. Similarities Between Electronegativity and Polarity
– Outline of Common Features
4. Difference Between Electronegativity and Polarity
– Comparison of Key Differences
5. FAQ: Electronegativity and Polarity
– Frequently Asked Questions
Key Terms
Electronegativity, Polarity
What is Electronegativity
Electronegativity is the measure of an atom’s tendency to attract electrons towards itself when forming a chemical bond. The higher the electronegativity of an atom, the stronger its pull is. Electronegativity values generally increase moving from left to right across a period (row) and decrease going down a group (column). Fluorine is the most electronegative atom in the periodic table, while metals like francium have the least electronegativity.
When two atoms with similar electronegativity bond together with equal force, they share the electrons equally, resulting in a covalent bond. When there is a difference in the electronegativities of the two atoms in the bond, the electrons get pulled towards the atom with the higher electronegativity. This creates a polar covalent bond. Polar molecules, with their uneven electron distribution, can form attractions with other polar molecules, influencing everything from the structure of water to the behavior of biological molecules.
What is Polarity
Polarity is the distribution of electrical charge among atoms connected by a chemical bond. Whenever there is a difference in electronegativity between the two atoms in a bond, electrons of the bond are pulled towards the more electronegative atom. This unequal pull creates distinct regions of partial positive and negative charge, making the molecule polar.
Atoms like oxygen and fluorine are highly electronegative, attracting electrons strongly, while elements like hydrogen are less electronegative. When two atoms with differing electronegativity form a covalent bond, the more electronegative atom attracts the electron cloud closer, distorting the symmetrical sharing and creating a dipole moment—a separation of positive and negative charge within the molecule. The greater the electronegativity difference, the stronger the dipole moment and the more polar the molecule.
In dissolution, polar molecules dissolve in other polar solvents composed of polar molecules, as seen in sugar dissolving in water. Nonpolar molecules, on the other hand, dissolve in nonpolar solvents. Polarity also influences physical properties such as boiling and melting points. Polar molecules require more energy to overcome the intermolecular attractions between them, resulting in higher boiling and melting points observed in certain substances.
Similarities Between Electronegativity and Polarity
- Both electronegativity and polarity are centered around the concept of an atom’s attraction for electrons.
- They involve the formation of regions of partial positive and negative charge within molecules.
Difference Between Electronegativity and Polarity
Definition
- Electronegativity is the measure of an atom’s tendency to attract electrons towards itself when forming a chemical bond, while polarity is the distribution of electrical charge among atoms connected by a chemical bond.
Atom vs Molecule
- Electronegativity is a property of an individual atom. Polarity, on the other hand, is a property of a molecule.
Applicability
- Electronegativity is a universal concept applicable to all elements, while polarity only applies to molecules with unequal electron sharing.
Measurement
- Electronegativity is measured on a relative scale, while polarity doesn’t have a single numerical value.
Conclusion
Electronegativity measures an atom’s attraction for electrons in a bond, influencing the creation of polar covalent bonds. Polarity, meanwhile, arises from the unequal sharing of electrons between atoms, leading to regions of partial positive and negative charge within a molecule. This is the main difference between electronegativity and polarity.
FAQ: Electronegativity and Polarity
1. What is the relationship between polarity and electronegativity?
The relationship between electronegativity and the polarity of a chemical bond is that the greater the difference in electronegativity between the two atoms, the more polar the chemical bond will be.
2. Is electronegativity directly proportional to polarity?
Yes, electronegativity is directly proportional to polarity. The greater the difference in electronegativity between the two atoms, the more polar the chemical bond will be.
3. Is H2O polar or nonpolar?
H2O is a polar molecule. An oxygen atom in the water molecule is higher in electronegativity than the hydrogen atoms in the same.
4. What causes polarity?
Polarity arises due to differences in electronegativity between atoms involved in a chemical bond. When atoms with varying electronegativities bond, the more electronegative atom attracts the shared electrons more strongly, creating partial charges within the molecule. This uneven distribution of charge results in a polar molecule.
Reference:
1. “Electronegativity.” Wikipedia. Wikipedia Foundation.
2. “Polarity Chemistry.” Encyclopedia Britannica.
Image Courtesy:
1. “Electronegative” By Adblocker – Own work (CC BY-SA 3.0) via Commons Wikimedia
2. “Water-elpot-transparent-3D-balls” (Public Domain) via Commons Wikimedia
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