1. CHAPTER 5 PERIODIC TABLE
Periodic Law and Electron Configurations
The “first” Periodic Table of the Elements
most credit given to ______________________ when? ________
(about ________ elements known)
he arranged the elements by __________________________
and grouped them according to ________________________
he gets the most credit because he dealt with two important issues…
to group the elements with respect to their similar properties,
1. he had to ____________________________________
predicted (correctly) ___________________________
2. and he had to ___________________________________
_________________________________________
predicted (incorrectly) _______________________
Dmitri Mendeleev
1860’s 60
increasing atomic mass
similar properties
leave blanks in his periodic table
blanks corresponded to elements
yet to be discovered
place some elements out of order
with respect to mass
the masses were incorrect

3. Periodic Table “from the 19th century” – pg 161 in text ????????
atomic number established in 1913 (Moseley)
atomic mass
????? just an ordering number….
“out of order”
Mendeleev

4. without any understanding of atomic structure
Mendeleev was “so close” to right…

5. an integer number of positively charged particles (protons)
not until 1913 (some 55+ years later!) was the mass issue resolved…
Moseley (working in ___________________ lab)
determined the nucleus contained
______________________________
his work established the ___________________
_______________________________________
symbol ________
called ___________________
Rutherford’s
an integer number of positively charged particles
(protons)
number of protons
in the nuclei of atoms Z
atomic number
so, again, some 55 years after Mendeleev’s work,
the Periodic Law of the Elements was established…
what was important was not
ordering the elements with respect to mass
BUT
with respect to _____________________
atomic number

6. The Periodic Law of the Elements
When the elements are ordered with respect to increasing atomic number,
their physical and chemical properties show a periodic pattern
periodic – repeating at certain (predictable) intervals
- after every so many (8, 8, 18, 18, 32, 32 …) elements, there
is another element with similar properties
the elements with similar properties are
grouped into columns

7. noble gases
alkali metals
halogens
alkaline earth
metals
coinage
metals

8. The Periodic Law of the Elements
When the elements are ordered with respect to increasing atomic number,
their physical and chemical properties show a periodic pattern
periodic – repeating at certain (predictable) intervals
1913
- after every so many (8, 18, 32…) elements, there
is another element with similar properties
- the elements with similar properties are grouped into columns
(reminder… a (Scientific) Law lacks an ____________________)
explanation
the explanation for the Periodic Law of the Elements lies in
Atomic Theory (the structure of the atom)
the explanation for the groupings of the elements
is that elements in a group have similar properties
BECAUSE they have similar outer shell electron configurations
1927 Schrodinger model
so… if we know the electron configurations
we can predict and explain the properties of the elements

9. some patterns noted so far…
the outer shell corresponds to the row in the Periodic Table
the outer shell starts to be filled with the element in the 1st column
and
the outer shell is full with the element in the last column
so,
determine the ground state electron configuration patterns for each
group (column) of elements
focus on outer shell because it is those electrons
that have the greatest influence on properties