Mendeleev created the periodic table in 1869, organizing the elements by atomic mass and properties into rows called periods and columns called groups. The periodic table arranges the elements in order of increasing atomic mass, with elements placed in periods based on electron orbitals and groups based on valence electrons. Most elements are metals on the left side, with some metalloids in the middle and nonmetals on the right except for hydrogen.

1. THE PERIODIC
TABLE
Silvia Sanguinetti
Period Eight

2. Mendeleev
Mendeleev created the Period Table
Mendeleev’s version was published
in 1869 in Russia.
He put the elements in order by
their atomic mass and similar
properties.

3. Periods
The elements are organized horizontally on the
Periodic table in rows called periods.
The elements are placed in each period by how many
electron orbitals they have.
There are seven periods.

4. Groups
The elements are organized vertically on the Periodic
table in columns called groups.
The elements are placed in each group by how many
valence electrons they have.
There are eighteen groups.

5. Atomic Mass
The elements on the periodic table are arranged in
order by atomic mass.
The element with lowest atomic mass is Helium and
the element with the highest atomic mass is
Ununoctium.

6. Metals Element
Most of the elements on the Atomic Number
Symbol
Periodic Table are metals.
The different kinds of metals are Density
Alkali Metals, Alkali Earth Melting Point
Metals, Lanthanoids, Actinoids, Atomic Mass
Transition Metals, and Post-
Transition Metals. Gold is a Transition Metal
Metals are on the left side of the
Period Table.

7. Metalloids
Element
Atomic Number
Symbol
There are seven elements on
the Periodic Table that are
metalloids.
Atomic Mass Density
Metalloids are on the right
side of the Period Table
between the Metals and the
Non-Metals. Melting Point Boiling Point

8. Nonmetals
Element
Atomic Number
Symbol
The rest of the elements on the
Periodic Table are Nonmetals.
Atomic Mass Density
The different kinds of
Nonmetals are Halogens, Noble
Gases and Other Nonmetals. Melting Point
Boiling Point
All of the Nonmetals are on the Helium is a Noble Gas.
right side of the Periodic Table
except Hydrogen.