Electron
Configurations
Mr. Scott
Electron Configurations:
 Electrons
are arranged in energy levels or
energy states located around the nucleus
of the atom.
Electron Configuration
 The
energy levels contain certain
amounts of electrons (2, 8, 18, 32) that
are arranged in orbitals. Each orbital has
two electrons.
(Energy level III can have
_18___ total electrons
meaning it contains _9__
orbitals.
Electron Configuration
 Orbitals
are areas where electrons are
commonly seen and they have an
associated shape to them.
Electron Configuration
 Electrons
fill orbitals of lower energy first,
each orbital contains two electrons, and
the electrons will have opposite spins.
Electron Configuration
 When
writing electron configurations use
the following flow chart to fill the orbitals in
the correct order from lowest energy to
highest:
Carbon




Determine # of electrons. If carbon has six protons
then a neutral atom of C will have six electrons.
Carbon = 1s2 2s2 2p2
(Carbon has six electrons: two electrons are in the
“s” orbital of energy level 1, two electrons are in
the “s” orbital of energy level 2 and two electrons
are in the p orbitals of energy level 2).
To help check your work the exponents should
add up to the number of electrons for the atom.
Hydrogen
 Atomic


number = 1
1 proton
If neutral = 1 electron
1s1
Lithium

Atomic number = 3


3 protons
3 electron (if atom is neutral)
1s2
2s1
Carbon

Atomic number = 6


6 protons
6 electron (if atom is neutral)
1s2
2s2
2p2
Iodine