Question

A covalent bond is formed between the atoms by the overlapping of orbitals containing (1) a single electron (2) paired electron (3) single electrons with parallel spin (4) single electron with opposite spin

Short answer

The correct option is (4) single electron with opposite spin.

Step-by-step solution

Understanding Covalent Bonds

A covalent bond is a type of chemical bond where atoms share pairs of electrons. This typically happens to achieve a full outer electron shell, resembling the noble gas configuration.

Electron Configuration in Covalent Bonds

Atoms involved in a covalent bond share electrons to achieve stability. The shared electrons occupy overlapping orbitals.

Condition for Overlapping of Orbitals

For orbitals to overlap and form a covalent bond, each participating atom must contribute a single unpaired electron. These electrons must have opposite spins to comply with the Pauli Exclusion Principle.

Identifying the Correct Option

Among the given choices, the correct scenario for covalent bond formation involves the overlapping of orbitals containing single electrons with opposite spins.

Key concepts

Electron Sharing

When we talk about covalent bonds, electron sharing is the key. Covalent bonds happen when two atoms share electrons to achieve greater stability. Think of it as teamwork where each atom contributes one or more electrons to form a shared pair.

By sharing electrons, atoms can fill up their outer electron shells, achieving a stable electron configuration similar to the noble gases. This sharing allows them to be more stable than they would be alone. Imagine two people sharing an umbrella; together, they stay dry.

- **Shared electron pairs** create the bond.
- The bond is mainly to achieve stability.
- Noble gas configuration is the goal.

Orbital Overlap

For a covalent bond to form, it's not just about sharing electrons; these electrons must come from overlapping orbitals. Orbitals are the spaces around an atom where electrons are likely to be found. When two atoms approach each other, their orbitals can overlap, allowing electrons to be shared.

Think of orbitals like rooms. When two rooms overlap, the shared space allows people (or electrons) to move easily between them.

- **Overlapping orbitals** are essential for covalent bonds.
- Overlap allows shared electrons to 'belong' to both atoms.

If the orbitals don't overlap, electrons can't be shared effectively, and no bond forms. So, orbital overlap is crucial for the stability and existence of covalent bonds.

Pauli Exclusion Principle

The Pauli Exclusion Principle might sound complex, but it's quite simple. It states that no two electrons in an atom can have the same set of quantum numbers. In the context of covalent bonds, it means that the shared electrons must have opposite spins.

Electrons can spin in two directions - imagine one spinning up and another spinning down.

- **Opposite spins** are necessary for electron sharing in covalent bonds.
- Spin ensures each electron remains distinct according to Pauli Exclusion Principle.

This opposite spin requirement ensures that shared electrons do not violate the principle, making the bond stable and compliant with the rules of quantum mechanics.

Electron Configuration

Electron configuration describes the arrangement of electrons in an atom's orbitals. When atoms form covalent bonds, their electron configurations change. By sharing electrons, they achieve full outer shells, leading to stability.

Atoms tend to follow the **Octet Rule**, striving to have 8 electrons in their outer shell. When two hydrogen atoms share electrons, each achieves the electron configuration of helium.

- **Electron configuration** aims for stable arrangements like noble gases.
- Covalent bonds help achieve full outer shell configurations.

Understanding electron configuration helps us predict how atoms will bond and what the resulting molecules will look like. It's the blueprint for stability in chemistry.