The periodic table of chemical elements, often called the periodic table, organizes all discovered chemical elements in rows (called periods) and columns (called groups) according to increasing atomic ...

Eighty out of the first 82 elements in the periodic table have stable isotopes. Measuring and analysing their distribution allows for many practical applications. The IAEA assists Member States in ...

Currently, there are 118 known elements on the periodic table, from hydrogen all the way ... But scientists predict that elements will remain intact and stable for longer than current known ...

Elements in group 1 and group ... have a full outer electron shell, so are very stable. See the study guide on groups in the periodic table for more information.

Scientists have found that our bodies need 28 different elements to function properly. These are almost one-quarter of the periodic table and are mainly found in the first four periods.

When Mendeleev first proposed his periodic table in 1869 he left gaps for elements ... Many false claims were made before it was realised that the missing element would be radioactive with no stable ...