The periodic table arranges elements by increasing atomic number.

Elements in the same group have similar properties.

Metals are on the left; nonmetals are on the right of the table.

The table is divided into periods (rows) and groups (columns).

Noble gases in group 18 are very unreactive.

Alkali metals in group 1 are very reactive with water.

Transition metals are found in the middle of the table.

The periodic table was created by Dmitri Mendeleev in 1869.

Elements are classified as metals, nonmetals, or metalloids.

Each element has a unique chemical symbol.