S orbital

Definition

An s orbital is a spherical region around the nucleus of an atom where the probability of finding an electron is highest. It is the simplest type of atomic orbital and can hold a maximum of two electrons with opposite spins. In many-electron atoms, the presence of s orbitals plays a crucial role in determining electron configurations, which describe the arrangement of electrons in an atom.

5 Must Know Facts For Your Next Test

1. The s orbital is present in every energy level, starting from the first principal energy level (n=1).
2. Each s orbital has a spherical shape, which reflects the symmetry in the distribution of electron density around the nucleus.
3. The first energy level has one s orbital (1s), while higher energy levels have additional orbitals (2s, 3s, etc.), with each s orbital being able to hold two electrons.
4. In many-electron atoms, electrons fill lower-energy orbitals first (Aufbau principle), which means s orbitals are filled before p orbitals.
5. The presence of electrons in s orbitals significantly influences chemical properties such as bonding and reactivity due to their proximity to the nucleus.

Review Questions

• How do s orbitals influence the electron configurations of many-electron atoms?
  • In many-electron atoms, s orbitals are filled before p, d, or f orbitals according to the Aufbau principle. This filling order means that s orbitals play a key role in determining the overall electron configuration and stability of an atom. The electrons in these lower-energy s orbitals help define an atom's chemical behavior and reactivity since they are closest to the nucleus.
• Compare and contrast s orbitals with p orbitals in terms of shape and electron capacity.
  • S orbitals have a spherical shape and can hold a maximum of two electrons, while p orbitals have a dumbbell shape and can hold up to six electrons across three p suborbitals. The differences in shape affect how these orbitals interact during chemical bonding. For example, when forming bonds, the spatial arrangement of p orbitals allows for directional bonding compared to the isotropic nature of s orbitals.
• Evaluate the significance of the Pauli Exclusion Principle and its effect on electron placement in s orbitals within many-electron atoms.
  • The Pauli Exclusion Principle states that no two electrons can occupy the same quantum state simultaneously. This principle necessitates that when two electrons occupy an s orbital, they must have opposite spins. As a result, only two electrons can reside in an s orbital regardless of how many higher energy levels are available for additional electron occupancy. This limitation affects how electron configurations are established for many-electron atoms and ultimately influences their chemical properties.

Related terms

Atomic Orbital: A region in an atom where there is a high probability of finding electrons, characterized by distinct shapes and energy levels.

Electron Configuration: The distribution of electrons in an atom's orbitals, usually described using a notation that indicates the types and numbers of orbitals occupied.

Pauli Exclusion Principle: A principle stating that no two electrons in an atom can have the same set of four quantum numbers, which leads to the arrangement of electrons in orbitals.