Aim: How do chemists represent an atom’s “electron configuration”? Vocabulary: Electron configuration- probable location of electron; the electron’s “address.” Quantum model (wave-mechanical)- electrons have the properties of both particles and waves. Orbital- region of space in which you can expect to find electrons of specific energy.

Aim: How do chemists represent an atom’s “electron configuration”? Rules for writing electron configurations: Each added electron is placed into the sublevel of lowest available energy. (Aufbau principle.) No more than two electrons can be placed in any orbital. (Pauli exclusion principle.) A single electron must be placed into an orbital of a given sublevel before any pairing takes place. (Hund’s rule.) The outermost principal energy level can only contain electrons in “s” and “p” sublevels.

Aim: How do chemists represent an atom’s “electron configuration”? Essential Questions : Compare and contrast Bohr model with modern quantum model. Distinguish between orbit and orbital Write the electron configuration and draw orbital diagram for an atom of aluminum, the element used in fireworks to create a bright white light. Describe the evolution of atomic theory.