1. What is the periodic table?
• The periodic table is a chart of the
elements arranged into rows and
columns according to their physical
and chemical properties.
• It can be used to determine the
relationships among the elements.

2. Atomic Number
Atomic Number
11
11
Na
Na Element symbol
Element symbol
Sodium
Sodium
22.990
22.990 Element name
Element name
Atomic Mass
Atomic Mass
11
11
Atomic # = ______
22.990
22.990
Atomic Mass = _________
23
23
Mass # = _________
11
11
# of Protons = ________
12
12
# of Neutrons = ________
11
11
# of Electrons = ________

3. Arranged according
Arranged according
to similarities
to similarities
or patterns
or patterns

4. Today’s Periodic Table
You can identify many of the properties of an
element from its placement on the periodic
table.

5. The table is organized into columns, rows, and
blocks, which are based on certain patterns of
properties.

6. Today’s Periodic Table (cont.)
• A group is a column on the periodic table.
• Elements in the same group have similar
chemical properties and react with other
elements in
similar ways.

7. Today’s Periodic Table (cont.)
What can you infer about the
properties of two elements in
the same group?

8. Today’s Periodic Table (cont.)
• The rows on the periodic table are
called periods.
• The atomic number of each element
increases by one as you read from left
to right across each period.