1. Periodic Table:
Periods: Are the horizontal rows on the
Periodic Table.
All elements in the same period contain the same number of energy levels.
Valence electrons: Electrons in the outermost energy level of the atom.
The number of valence electrons increases by one across a period.

2. Periodic Table:
Groups-A number = # of valence electrons
Ex.
Elements in group 1A – contain 1 valence e-
Elements in group 3A – contain 3 valence e-
Elements in group 7A – contain 7 valence e-

3. Metals, Nonmetals, and Metalloids

4. Periodic Table:
Metals – Located on the left side of the
stair-step line (they are solids, except
Mercury which is liquid)
Nonmetals– Located on the right side
(solids, liquids, or gases).
Metalloids: Located between metals &
nonmetals (touching the
stair-step line).

5. Periodic Table:
Groups: Vertical columns (elements in
the same group have similar
properties).
Group 1A: The most reactive metals
(Alkali metals).
Group 2A : Reactive metals also
(Alkaline Earth metals).
Group 7A: The most reactive non metals
(Halogens).
Group 8A: Unreactive, very stables.
(Noble gases).

6. Periodic Table:
The Periodic Table is divided into four different blocks:
1) s-block: Its valence electrons occupy
only “s” orbitals.
s-block: Group 1A & 2A

7. Periodic Table:
2) p-block: The outermost electron
occupy “p” orbitals.
p-block: Group 3A - 8A

8. Periodic Table: s-block Representative or group A elements p-block

9. Periodic Table:
3) d-block: They have a filled outermost “s” orbital & partially filled or filled “d” orbitals in energy level (n-1).
d-block: Groups B, the transition metals

10. Periodic Table:
4) f-block: The outermost electron is
placed in “f” orbitals.
f-block: The inner transition metals

11. Periodic Table (Blocks):
“s” block
“p” block
“d” block
Representative
Representative
Transition Metals
“f” block
Inner Transition Metals

12. Classification of Groups: