Electron Configuration
ORBITAL NOTATION
ELECTRON CONFIGURATION NOTATION
NOBLE GAS NOTATION
FOLLOW ALONG STARTING ON P.111 IN YOUR
TEXTBOOK
What is electron configuration?
 It is simply the arrangement of electrons in an atom.
 There are 3 basic rules, or principles, that determine
how electrons will be arranged:
the Aufbau principle (this will lead to some d-block exceptions
later)
 the Pauli exclusion principle
 Hund’s rule
*Find each definition in your textbook and write it down. We will
briefly discuss each after they are written.

What does it all mean?
 Electrons are arranged in main energy levels,
sublevels and orbitals.


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The main energy levels are numbered 1 through 7.
The sublevels can be s, p, d, or f
Each sublevel will have an odd number of orbitals that can
hold 2 electrons each.
S has 1 orbital = _______ electrons
 P has 3 orbitals = _______ electrons
 D has 5 orbitals = _______ electrons
 F has 7 orbitals = _______ electrons

Electron Configuration Notation
 This notation contains only numbers, letters, and
exponents to represent the number of electrons in
each sublevel.
 Each electron configuration notation will start with a
Hydrogen configuration (1s1) and continue in order
following the periodic table (or figure 16 on p.111, or
figure 19 on p.116)
Examples
 Hydrogen
 Neon
 Helium
 Silicon
 Lithium
 Calcium
 Boron
 Nitrogen
Orbital Notation
 The simplest way to notate an element’s electron
configuration is with each orbital represented and
each electron drawn.
 Each arrow represents one electron.
 Orbitals will fill with an up arrow first, then a
down arrow.

Multiple orbitals will each fill with an up arrow before being
completed with a down arrow.
LOTS of examples
 Hydrogen
 Neon
 Helium
 Silicon
 Lithium
 Calcium
 Boron
 Nitrogen
Noble Gas Notation
 This is the most common notation to find and the
easiest to write.
 Begin with the noble gas just before the element
that you are notating, then fill in the electron
configuration from there.
Examples
 Hydrogen
 Neon
 Helium
 Silicon
 Lithium
 Calcium
 Boron
 Nitrogen
Practice p.113
 Complete practice problems #1-2
d block elements
 The d block contains the transition metals from
periods 4 through 7.
 Normally, you would write the period number before
your block letter. However, when numbering the d
block, subtract 1 from the period number.
 So, the d block in the 4th period would be called 3d.
3d Examples
*3d is always written before 4s
Scandium
Iron
Titanium
Cobalt
Vanadium
Nickel
Chromium
Copper
Manganese
Zinc
4d examples
*4d is always written before 5s
Yttrium
Zirconium
Niobium
Molybdenum
Technetium
Ruthenium
Rhodium
Palladium
Silver
Cadmium
The f block
 The f block is unique for the following reasons:
 It makes the 6th and 7th periods much longer because they
are meant to be inserted right after Ba for the Lanthanides
and after Ra for the Actinides.
 When notating the f block, subtract 2 from the normal
period number (ex. Period 6 would be 4f).
 Technically, Lanthanum (La) and Actinium (Ac) are in the d
block (see the spaces?), so the Lanthanide notations will be
4f__5d16s2. Actinides will each be one number higher.
 You will not be required to complete any f-block
electron configurations, but you must be able to
explain how it is different from the s, p, and d
blocks.
Practice on your own
 Complete the practice problems on pages 121 and
p.122
 You will only need to create orbital notations for
elements in periods 1-4.
 You will be required to be able to complete an
electron configuration notation and a noble gas
notation for every element on the periodic table
through Barium.
Exceptions
 There are always exceptions to any rule (remember
the Aufbau principle?), and some elements do not
follow the order exactly as it is set in figure 19. You
must MEMORIZE the exceptions from the fourth
and fifth periods:
5 p.118
TABLE 6 p.120
TABLE
Assignment
 Complete the 4.3 section review on p.122
 (due by the end of class today)
 Your chapter review assignment will be due by the
end of class Monday:

Chapter 4: P.124 – 126 (#4-9, 15, 23-32, 35-41, 46)


25 problems
Chapter 5: p.166 – 169 (#1-4, 7-9, 11, 13-17, 22-25, 27-32, 35,
37, 44-50 even)

29 problems
 **This is a lot of problems! Don’t wait until
Monday to start or you will not finish!!