S orbital

Definition

An s orbital is a type of atomic orbital that is spherical in shape and can hold a maximum of two electrons. It is the simplest type of orbital, found in all energy levels, and serves as the foundational building block for understanding electronic configurations and energy levels. The presence of s orbitals in an atom plays a crucial role in determining the arrangement of electrons and the overall chemical behavior of elements.

5 Must Know Facts For Your Next Test

1. The s orbital is present in every energy level, starting from n=1, which means every atom has at least one s orbital.
2. Each s orbital can hold a maximum of two electrons, with opposite spins according to the Pauli Exclusion Principle.
3. The shape of an s orbital is spherical, which means the probability density of finding an electron is evenly distributed around the nucleus.
4. In multi-electron atoms, the energy levels of s orbitals are lower than those of p, d, and f orbitals within the same principal quantum number.
5. S orbitals are crucial in forming bonds; for instance, when two atoms bond, their s orbitals can overlap to create a sigma bond.

Review Questions

• How does the presence of s orbitals influence an atom's electron configuration?
  • S orbitals influence an atom's electron configuration by being the first type of orbital to be filled as energy levels increase. Starting from the lowest energy level (n=1), the 1s orbital is filled before any other orbitals in higher energy levels. This filling order follows Hund's rule and the Aufbau principle, ensuring that the most stable electronic configuration is achieved. Understanding how s orbitals fit into this configuration helps explain an element's reactivity and bonding behavior.
• Discuss the significance of the spherical shape of s orbitals in relation to electron probability density.
  • The spherical shape of s orbitals is significant because it reflects where electrons are most likely to be found around the nucleus. Since the probability density is evenly distributed in all directions from the nucleus, this means that an electron in an s orbital has equal chances of being located at any point along that sphere. This uniform distribution plays a vital role in chemical bonding as it allows for effective overlap with other orbitals during bond formation, especially sigma bonds.
• Evaluate how understanding s orbitals contributes to predicting chemical properties across different elements in the periodic table.
  • Understanding s orbitals allows us to predict chemical properties because these orbitals dictate how atoms interact based on their electron configurations. For instance, elements with completely filled s orbitals tend to be noble gases with low reactivity. Conversely, elements with partially filled s orbitals are more likely to lose or gain electrons during chemical reactions. This knowledge helps explain trends in reactivity, ionization energies, and electronegativities across different groups and periods in the periodic table.

Related terms

Atomic Orbitals: Regions around an atom's nucleus where there is a high probability of finding electrons, characterized by specific shapes and energy levels.

Electron Configuration: The distribution of electrons in an atom's orbitals, which determines its chemical properties and behavior.

Principle Quantum Number (n): A number that specifies the energy level of an electron in an atom and influences the size and energy of orbitals.