Overview
This lecture explains electron orbitals, how electrons fill these orbitals in atoms, and the notation for electron configurations, including the use of noble gas shorthand.
Orbitals and Subshells
- Orbitals describe the probability of finding an electron in a region around the nucleus.
- Subshells include s, p, d, and f, each containing different numbers of orbitals.
- An s subshell has 1 orbital (2 electrons max), p has 3 (6 electrons), d has 5 (10 electrons), f has 7 (14 electrons).
- Each orbital holds a maximum of 2 electrons.
Electron Configurations of Elements
- Electron configuration indicates how electrons are distributed among shells and subshells in an atom.
- Hydrogen (atomic number 1): 1s¹ (one electron in s orbital of first shell).
- Helium (atomic number 2): 1s² (two electrons fill the 1s subshell).
- Lithium (atomic number 3): 1s² 2s¹ (first shell filled, third electron in 2s).
- Beryllium (atomic number 4): 1s² 2s² (first and second s subshells filled).
- Boron (atomic number 5): 1s² 2s² 2p¹ (starts filling p subshell in second shell).
- Carbon (atomic number 6): 1s² 2s² 2p² (two electrons in 2p subshell).
Noble Gas Configuration Notation
- Noble gas configuration uses the previous noble gas to simplify electron configuration notation.
- Example: Carbon can be written as [He] 2s² 2p², with [He] representing 1s².
Key Terms & Definitions
- Orbital — A region with a high probability of finding an electron.
- Subshell — A group of orbitals within a shell (s, p, d, f).
- Electron configuration — The arrangement of electrons in an atom's shells and subshells.
- Noble gas configuration — Shorthand notation using a noble gas symbol to represent core electrons.
Action Items / Next Steps
- Practice writing electron configurations for the next 10 elements.
- Review the periodic table to identify noble gases for shorthand notation.