Classification of the
Elements
Objectives:
AHSGE Reading 4.3 Discern organizational
patterns.
Other AOD C.3.2 Recognize periodic trends of
elements, including the number of valence
electrons, atomic size, and reactivity.
Organizing the Elements by
Electron Configuration
• We know valence electron configurations
of the group A elements. Now let’s look at
valence electrons and periods.
• Write the noble gas configurations of the
group 1A elements straight down in a
column.
• What is the 1st trend you notice?
• What other trend do you see?
Organizing the Elements by
Electron Configuration
(continued)
• The energy level of the valence electrons
is the same as the period number the
element is found in!
• So in what energy level would the valence
electrons for gallium (Ga) be found?
• What about titanium (Ti)?
s-, p-, d-, and f- Block
Elements
• s-block elements have valence electrons
in the s orbital.
• What groups would this be?
• p-block elements are found in groups 3A8A.
• This block’s elements have filled or
partially filled p orbitals.
• How many groups on the periodic table
are in the p-block? Why is this so?
s-, p-, d-, and f- Block
Elements (continued)
• The first period contains NO p-block
elements. The first p-block element is
boron.
• What period is boron in?
• Why are there no p-block elements in the
first period?
Answer: The 1st period elements only have
a 1s orbital.
s-, p-, d-, and f- Block
Elements (continued)
• d-block elements are the transition
metals.
• USUALLY contain a filled outermost sorbital of energy level n, and a filled or
partially filled d-orbital of energy level n-1.
• Example: Scandium (Sc) is in period ___.
• Sc has a filled 4s orbital and a partially
filled 3d orbital.
s-, p-, d-, and f- Block
Elements (continued)
• So what s-orbital and what p-orbital would
be filled or partially filled for tungsten
(W)?
Answer: 6s and 5p.
• How many d orbitals are there?
Answer: 5
• How many electrons can those d orbitals
hold?
Answer: 10
s-, p-, d-, and f- Block
Elements (continued)
• How many “groups” (columns) does the
d-block span on the periodic table?
• f-block elements are the inner transition
metals.
• Characterized by a filled or partially filled
outermost s-orbital, and filled or partially
filled 4f or 5f orbital.
• f-orbitals do not fill in a predictable
manner.
Overview/Review
1. Moving DOWN through the periods, the
principal energy level increases.
2. As principal energy level increases, so
does the number of energy sublevels
containing electrons.
3. Period 1 has only s-block elements.
4. Periods 2 and 3 have s- and p-orbitals.
5. Periods 4 and 5 have s-, p- and dorbitals.
6. Periods 6 and 7 have ??????
Assignments 
1. Practice Problems, p.162 (7-9)
2. In which block of the periodic table
would each of the elements identified in
#9 be found?
3. Complete Study Guide for Content
Mastery, pp.33-34 (16-26).