Oxidation Number and Electron Distribution in Covalent Bonds

The oxidation number of an element in a compound is a measure of the electrical charge that element carries when it is part of that compound. It helps in determining the electron distribution in a covalent bond. The correct answer to the given question is option 'A', which states that the electrons in a covalent bond belong entirely to the more electronegative element. Let's discuss this in detail.

Understanding Covalent Bonds
In a covalent bond, two atoms share electrons to achieve a stable electron configuration. Each atom contributes one or more electrons to the shared pair. The shared electron pair forms a bond between the atoms, holding them together. Covalent bonds usually occur between nonmetals, and they can be polar or nonpolar depending on the electronegativity difference between the atoms.

Electronegativity and Electron Distribution
Electronegativity is the ability of an atom to attract electrons towards itself in a chemical bond. The more electronegative an atom is, the greater its ability to attract electrons. In a covalent bond between two different atoms, the electronegativity difference determines the distribution of electrons.

Explanation of Option 'A'
Option 'A' states that the electrons in a covalent bond belong entirely to the more electronegative element. This means that the element with higher electronegativity attracts the shared electrons more strongly, giving it a partially negative charge. The other element, with lower electronegativity, has a partially positive charge.

When determining oxidation numbers, we assign the shared electrons entirely to the more electronegative element. This is because the more electronegative element has a greater pull on the electrons and is considered to "own" them. The less electronegative element is assigned a positive oxidation number.

Example
Let's consider the covalent compound hydrogen chloride (HCl). Chlorine (Cl) is more electronegative than hydrogen (H), so the shared electron pair is assigned to chlorine. This gives chlorine a partial negative charge and hydrogen a partial positive charge. The oxidation number of chlorine in HCl is -1, and the oxidation number of hydrogen is +1.

In conclusion, the correct answer to the given question is option 'A' because the electrons in a covalent bond belong entirely to the more electronegative element. This principle helps in determining the oxidation numbers of elements in compounds.

Take the example of fluorine u can understand