Warm-Up: to be turned in
Identify the following atoms based on
the given electron configurations:
1s22s22p63s23p5
[Kr]5s24d105p1
1s22s22p4
[Ne] 3s1
1s22s22p63s23p64s23d7
Ch. 4/5:
Atomic Structure
Orbitals
Orbitals
 each
sublevel is broken into orbitals
 each orbital can hold a maximum of 2
electrons
 orbital-
a 3D region around the
nucleus that has a high probability of
holding electrons
Number of Orbitals
sublevel
s
p
d
f
max # e2
6
10
14
# orbitals
1
3
5
7
One s orbital
 spherical
Three p orbitals
 dumbbell-shaped
Five d orbitals
 various
shapes
Seven f orbitals
 various
shapes
Rules for Arrangements

Aufbau Principle- an
electron occupies the
lowest-energy orbital
that can receive it

Beginning in the 3rd
energy level, the
energies of the
sublevels in different
energy levels begin to
overlap
Rules for Arrangements
 Pauli
Exclusion Principle- no two
electrons in the same atom can have
the same set of 4 quantum numbers
 Hund’s Rule- orbitals of equal energy
are each occupied by one electron
before any orbital is occupied by a
second
 all unpaired electrons must have the
same spin
Writing Configurations
 Orbital



Notation:
an orbital is written as a line
each orbital has a name written below it
electrons are drawn as arrows (up and
down)
Rules for Arrangements
Writing Configurations
Start by finding the number of electrons in
the atom
 Identify the sublevel that the last electron
added is in by looking at the location in
periodic table
 Draw out lines for each orbital beginning
with 1s and ending with the sublevel
identified
 Add arrows individually to the orbitals until
all electrons have been drawn

Homework: Due 10/16/2012
 Write
the orbital notation for the
following elements:
Helium nitrogen neon nickel
bromine