Chemistry: Periodic Table

There should be a Periodic Table of Elements at the bottom of this website.

The Periodic table sorts the elements from least to greatest by atomic number*.

The horizontal rows called groups contain elements with similar properties. The similarities result from the fact that elements in a group have similar arrangements of electrons at their outermost
border or shell.

As you move across a period, however, the properties of the elements tend to change gradually.
This slow change results mostly because the elements have different electron arrangements at
their outermost shell. By the time you reach the right edge of the periodic table, the elements’ outermost shells are completely full.

It is actually quiet organized.

*The number of protons.

Sources: Chemistry workbook for Dummies