Question

In a given chemical compound, there is a bond between "A" and "B". The electronegativities of the involved elements are, respectively, \(1.2\) and \(2.1\) What is the probable nature of the bond between "A" and "B"?

Short answer

The electronegativity difference between elements A and B is \(|2.1 - 1.2| = 0.9\). Since the difference is between 0.4 and 1.7, the probable nature of the bond between "A" and "B" is a polar covalent bond.

Step-by-step solution

Calculate the electronegativity difference

We are given the electronegativities of elements A and B as 1.2 and 2.1. We will subtract the smaller electronegativity value from the larger one to find the difference: Electronegativity difference = \(|2.1 - 1.2|\)

Determine the bond nature

Now that we have the electronegativity difference calculated, we can use the Pauling Scale to determine the type of bond between element A and element B. Electronegativity difference = \(|2.1 - 1.2| = 0.9\) Since the difference is between 0.4 and 1.7, the probable nature of the bond between "A" and "B" is a polar covalent bond.

Key concepts

Electronegativity

Electronegativity is a chemical property that describes an atom's ability to attract and hold onto electrons within a chemical bond. It gives us insight into how atoms will interact with each other when they form compounds. The electronegativity of an element is often represented numerically, allowing us to predict the behavior of atoms in a bond.

In practical terms, the higher the electronegativity of an atom, the more strongly it can pull electron density toward itself. This difference in the ability to attract electrons affects the type and characteristics of the bond formed between two atoms.

• Atoms with similar electronegativities tend to form nonpolar covalent bonds.
• A significant difference in electronegativities usually leads to polar covalent bonds or even ionic bonds in the case of very large differences.

Recognizing the electronegativity values of elements helps make predictions about the molecule's stability, reactivity, and behavior in different chemical reactions.

Polar Covalent Bond

A polar covalent bond arises when there is an unequal sharing of electrons between two atoms in a molecule. This results from differences in electronegativity between the bonded atoms. In our example with elements A and B, an electronegativity difference of 0.9 indicates a polar covalent bond.

This type of bond is characterized by a partial negative charge on the more electronegative atom and a partial positive charge on the less electronegative atom. This creates a dipole moment within the molecule, with one end slightly negative and the other slightly positive.

• The larger the difference in electronegativity, the more polar the bond.
• Polar covalent bonds are common in molecules like water (H2O), where the oxygen atom is more electronegative than hydrogen atoms, leading to unequal sharing of electrons.

Understanding polar covalent bonds helps explain molecule shapes, intermolecular forces, and chemical reactions.

Pauling Scale

The Pauling Scale is the most widely used scale for measuring electronegativity. Named after Linus Pauling, it assigns electronegativity values to elements that range from around 0.7 to 4.0, with fluorine being the most electronegative element at 4.0.

The scale allows us to quantitatively predict the potential nature and strength of the bond between two atoms.

• A small difference on the Pauling Scale suggests a nonpolar covalent bond.
• An intermediate difference, like the 0.9 difference we calculated, suggests a polar covalent bond.
• A large difference typically indicates ionic bonding, as electrons are not shared but transferred.

The Pauling Scale is a powerful tool for chemists, helping them make quick assessments about chemical structures and properties based on electronegativity.