Periodic Table of Elements
Periodic Table of Elements
Overview
- The periodic table is a visual model that organizes chemical elements so their relationships and recurring properties can be seen at a glance. Its layout turns a list into a map: position encodes atomic number and recurring patterns in chemical behavior.
History
- Earlier chemists proposed ways to classify elements. In 1869, Dmitri Mendeleev published a table that grouped elements by recurring properties and atomic weight. He left gaps where the pattern suggested undiscovered elements and predicted some of their properties.
- In 1913, Henry Moseley's measurements connected element order to atomic number. Ordering by atomic number resolved cases where atomic weight alone put neighboring elements in the wrong order.
How the representation works
- Each cell represents one element and commonly shows its atomic number, symbol, name, and atomic mass.
- Rows, called periods, follow increasing atomic number. Columns, called groups, collect elements with related chemical behavior.
- The shape makes periodic patterns visible and allows position to convey information about an element's structure and likely behavior.
Sources