Download Electron Arrangement in an Atom

Electron Arrangement in an
Atom
Electron Configuration
• The ways in which electrons are arranged
into various orbitals around the nuclei of
atoms.
• To find electron configuration we rely on
three rules:
• The aufbau principle
• The Pauli exclusion principle
• Hund’s Rule
Aufbau Principle
• Electrons occupy the orbitals of lowest energy
first.
• The range of energy levels of a principle level can
sometimes overlap the energy levels of another
principle level (Look below)
Pauli’s Exclusion Principle
• An atomic orbital may describe at most
two electrons .
• One or two electrons can occupy an orbital
of any sublevel.
• If two occupy the same orbital, they must
have opposite spins
Hund’s Rule
• Electrons occupy orbitals of the same energy in a way
that makes the number of electrons with the same spin
as large as possible.
• After, a second electron enters the orbitals so that each
is paired with opposite spins
Electron Configuration
• If I tell you that the exponents are the number of
electrons, what elements have the following
electron configurations:
1.) 1s22s22p1
2.) 1s22s1
3.) 1s22s22p63s2
1.) Boron (B)
2.) Lithium (Li)
3.) Magnesium (Mg)
What is the electron configuration
of the following elements?
1.) Hydrogen
2.) Ne
3.) Potassium
1.) 1s1
2.) 1s22s22p6
3.) 1s22s22p63s23p64s1
Now use those electron configurations to fill an
orbital diagram with electron spins
• Check the website!