U3L3 - Lecture Notes - Electron Configurations

Ground-State Electron Configuration

Electron Configuration
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Ground-State Electron
Configuration

• The Pauli exclusion principle states that
a maximum of two electrons can occupy
a single orbital, but only if the electrons
have opposite spins.

• Hund’s rule states that single electrons
with the same spin must occupy each
equal-energy orbital before additional
electrons with opposite spins can
occupy the same energy level orbitals.

Electron Configuration
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Ground-State Electron Configuration

• The aufbau diagram can be used to write correct ground-state electron
configurations for all elements up to and including Vanadium, atomic number 23.

• The electron configurations for certain transition metals, like chromium and copper, do not follow the aufbau diagram due to increased stability of half-filled and filled sets of s and d orbitals.

Electron Configuration
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Valence Electrons

• Valence electrons are defined as
electrons in the atom’s outermost
orbitals—those associated with
the atom’s highest principal
energy level.

• Electron-dot structure consists
of the element’s symbol
representing the nucleus,
surrounded by dots representing
the element’s valence electrons.

Electron Configuration
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