An Introduction to Chemistry

Electron
Configurations (cont

t.)

Order of
Orbital Filling

1s 2s 2p 3s 3p 4s 3d 4p 5

5s 4d 5p 6s 4f 5d 6p 7s 5f 6d 7p

Second Period
Electron
Configurations



Writing Electron
Configurations

•  Determine the nu
atom from its atom

•  Add electrons to t
correct order of fil

•  Add two electrons
each p sublevel, 1
and 14 to each f s

•  To check your co
configuration, loo
location of the las
corresponds to th
the periodic table

umber of electrons in the
mic number.
the sublevels in the
lling.
s to each s sublevel, 6 to
10 to each d sublevel,
sublevel.
omplete electron
ok to see whether the
st electron added
he element’s position on
e.

Order of Filling from
the Periodic Table

m

Long Periodic
Table



Drawing Orbital
Diagrams

•  Draw a line for ea
mentioned in the c
configuration. Dra
sublevel, three lin
lines for each d su
each f sublevel.

•  Label each sublev
•  For orbitals contai

one arrow up and
the electrons’ opp
•  For unfilled sublev

ach orbital of each sublevel
complete electron
aw one line for each s
nes for each p sublevel, five
ublevel, and seven lines for

vel.
ining two electrons, draw
d one arrow down to indicate
posite spin.
vels, follow Hund’s Rule.

Abbreviated Electro
Configurations

•  The highest energ
important for chem

•  The noble gas con
especially stable a
for chemical bond

•  We often describe
reflect this represe
electrons with a n
brackets.

•  For example, for s
1s2 2s2 2p6 3s1

on

gy electron are most
mical bonding.
nfigurations of electrons are
and, therefore, not important
ding.
e electron configurations to
enting the noble gas
noble gas symbol in
sodium
goes to [Ne] 3s1

Writing Abbreviated
Electron Configuratio

•  Find the symbol f
periodic table.

•  Write the symbol
gas located at the
horizontal row on

•  Move back down
containing the ele
describe) and to t
elements in the ro
the outer-electron
with each column
element you are d

ons

for the element on a
in brackets for the noble
e far right of the preceding
n the table.
a row (to the row
ement you wish to
the far left. Following the
ow from left to right, write
n configuration associated
n until you reach the
describing.

Abbreviated Electron
Configurations –
Optional Step

•  Rewrite the a
electron conf
the sublevels
increasing pr
level (all of th
4’s, all of the
5’s, etc.)

n
abbreviated
figuration, listing
s in the order of
rincipal energy
he 3’s before the
e 4’s before the

Group 1 Abbreviated
Electron
Configurations



Abbreviated Electron
Configuration Steps
for Zinc

n

Common
Mistakes

•  Complete electron c
electrons (Use the p
order of filling.)

•  Orbital diagrams – f
unpaired with the sa
electrons to the p, d

•  Abbreviated electro
–  Forgetting to put
–  Forgetting to list
increasing princip

configurations – miscounting
periodic table to determine

forgetting to leave electrons
ame spin when adding
d, or f sublevels (Hund’s Rule)
on configurations
t 4f14 after [Xe]
sublevels in the order of
pal energy level