Electron-electron repulsion

Definition

Electron-electron repulsion refers to the force that pushes electrons apart due to their like charges, which is a fundamental aspect of electromagnetic interactions. This repulsion plays a crucial role in determining the arrangement of electrons around an atomic nucleus and significantly influences the structure and properties of multi-electron atoms. Understanding this force helps explain why electrons occupy different orbitals and how they interact within atoms governed by the Pauli exclusion principle.

5 Must Know Facts For Your Next Test

1. Electron-electron repulsion is a key factor in determining the shape and size of atomic orbitals, influencing how atoms bond with each other.
2. In multi-electron atoms, electrons are arranged in different energy levels and sublevels to minimize their repulsion from one another, which stabilizes the atom.
3. The repulsion between electrons leads to a phenomenon known as shielding, where inner electrons partially block outer electrons from experiencing the full charge of the nucleus.
4. As more electrons are added to an atom, the effects of electron-electron repulsion increase, leading to variations in atomic radii across different elements.
5. Understanding electron-electron repulsion is essential for predicting chemical behavior and reactivity, as it affects how atoms interact during chemical bonding.

Review Questions

• How does electron-electron repulsion influence the arrangement of electrons in multi-electron atoms?
  • Electron-electron repulsion causes electrons to spread out in such a way as to minimize their interactions with one another. This results in electrons occupying different orbitals at varying energy levels. By distributing themselves this way, electrons can lower their potential energy, making the atom more stable. The arrangement also follows the Pauli exclusion principle, ensuring that no two electrons share the same set of quantum numbers.
• Discuss the role of electron-electron repulsion in determining atomic size and how it varies across different elements.
  • Electron-electron repulsion directly affects atomic size by influencing how closely electrons can approach each other. In smaller atoms, where there are fewer electron shells, the repulsion is more significant among closely packed electrons, leading to smaller radii. As more electron shells are added in larger elements, while overall shielding occurs, the effective nuclear charge felt by outer electrons diminishes due to increased distance from the nucleus and increased electron repulsion. This results in larger atomic sizes for heavier elements.
• Evaluate how electron-electron repulsion contributes to chemical bonding and molecular structure.
  • Electron-electron repulsion plays a pivotal role in chemical bonding by influencing how atoms interact when forming molecules. It dictates that shared electrons must be paired with opposite spins within molecular orbitals while minimizing repulsive forces between them. This balance between attraction (from nuclei) and repulsion (between electrons) shapes molecular geometry and determines bond angles. A clear understanding of this repulsion helps predict molecular shapes according to VSEPR theory and rationalizes various chemical properties such as polarity and reactivity.

Related terms

Pauli Exclusion Principle:

A quantum mechanical principle stating that no two fermions, such as electrons, can occupy the same quantum state simultaneously within an atom.

Orbital: A region in space around an atomic nucleus where there is a high probability of finding an electron; orbitals have distinct shapes and energy levels.

Coulomb's Law:

A law describing the electrostatic force between charged particles, which states that like charges repel each other while opposite charges attract.