Key Concepts: Quantum Mechanical Model & Orbitals

Core Definitions

• Quantum Mechanical Model: The modern model of the atom that treats electrons as waves and defines probability regions (orbitals).
• Orbital: A region of space where there is a high probability of finding an electron.
• s Orbital: Spherical-shaped orbital; each energy level has one s orbital (holds 2 electrons).
• p Orbital: Dumbbell-shaped orbital; exists starting from the 2nd energy level (3 orbitals, holds 6 electrons).
• d Orbital: Clover-shaped orbital; exists starting from the 3rd energy level (5 orbitals, holds 10 electrons).
• Heisenberg Uncertainty Principle: You cannot simultaneously know both the exact position and momentum of an electron.