Transcript Modern Atomic Theory II

Placement of Electrons
Rules for Filling Electrons
• Pauli Exclusion Principle- Orbitals can contain
a maximum of two electrons which must be of
opposite spin
• Aufbau Principle- Electrons enter and fill lower
energy orbitals before higher energy orbitals.
• Hund's Rule- When there are equal energy
orbitals available, electrons will enter the orbitals
one-at-a-time and only when all the orbitals are
half filled will pairing-up occur.
Order of energy levels
Orbital filling Diagram
Electron Location Notation
• A notation of where the electrons are
located in the ground state is called its
electron configuration.
• It is a notation that includes the energy
level, the type of orbital (s, p, d, f) and the
number of electrons in each orbital.
• The notation is unique to each element on
the periodic table.
Electron Configuration Notation
Examples of the First Ten Elements
Homework
• Pg 393 [30-40]