Question

Pauling scale of electronegativity of elements helps to determine (1) covalent nature of an clement (2) position of an clement in EMF series (3) dipole moment of molecules (4) polarity of bond

Short answer

Option 4: polarity of bond

Step-by-step solution

Understanding Electronegativity

Electronegativity is a measure of the tendency of an atom to attract a bonding pair of electrons. It is a dimensionless quantity and can be used to determine various properties of molecules and bonds.

Pauling Scale

The Pauling scale is a widely used method to quantify the electronegativity of elements. It was developed by Linus Pauling and is used to predict the polarity of bonds in molecules.

Analyzing the Options

Examine each given option: (1) Covalent nature of an element refers to the type of chemical bond, (2) Position in EMF series refers to the electrode potential, (3) Dipole moment is a measure of the separation of positive and negative charges, (4) Polarity of bond refers to the distribution of electrical charge over the atoms involved in the bond.

Linking Electronegativity to the Polarity of Bond

Electronegativity differences between bonded atoms can predict bond polarity. If the electronegativity difference is high, the bond is more polar. Hence, the Pauling scale of electronegativity primarily helps in determining the polarity of bonds.

Key concepts

Electronegativity

Electronegativity measures how strongly an atom attracts electrons in a chemical bond. Imagine it as an atom's ability to pull electrons towards itself. This property is really important because it helps us predict how atoms will interact with each other.
For instance, in a bond, if one atom has a higher electronegativity compared to the other, it will attract the bonding electrons more. This results in one atom having a slight negative charge and the other a slight positive charge.
To make things easier, scientists use different scales to measure electronegativity, the most common being the Pauling scale.

Polarity of Bond

When we talk about polarity of a bond, we are looking at how the electrons are spread out between two atoms in a bond.
If electrons are shared equally, it is a non-polar bond. If they are not shared equally, it is a polar bond.

• Non-polar bonds: Happen mostly between identical atoms like in O₂ or N₂.
• Polar bonds: Occur when there is a significant difference in electronegativity between the two atoms involved.

So, how do we determine the polarity? Using the electronegativity values from the Pauling scale, if the difference in electronegativity is large, the bond is considered polar. This difference in electronegativity leads to uneven distribution of charge across the bond.

Dipole Moment

Dipole moment comes into play when there is a separation of charges. It is a measure of the overall polarity of a molecule.
Even if a bond is polar, the molecule as a whole might not be. For example, carbon dioxide (CO₂) has two polar bonds but is a non-polar molecule because the two dipoles cancel each other out.
Calculation of dipole moment: A larger electronegativity difference and longer bond length will result in a higher dipole moment. The dipole moment (μ) can be represented mathematically as \( \text{μ} = q \times r \). Here, \( q \) is the magnitude of the charge, and \( r \) is the distance between the charges.

EMF Series

The EMF (Electromotive Force) series is a list of elements arranged by their standard electrode potentials.
This series helps us predict how different elements will act in redox reactions. Essentially, it tells us which elements are better at gaining or losing electrons.
Electronegativity plays a role here too. Higher electronegativity usually means the element is better at gaining electrons, and thus, is higher up in the EMF series.
Understanding an element's position in the EMF series can help in practical applications like predicting the outcome of chemical reactions and designing batteries.