Since then, the periodic table has evolved to reflect over 150 years of scientific development and understanding in chemistry and physics. Today, with 118 known elements, it is widely regarded as one ...

The periodic table The periodic table is a chart of all the elements arranged in increasing atomic number. Group 1 alkali metals The Group 1 elements, also known as the alkali metals, all react ...

But how many of these elements do you know? Test your knowledge and compete with other Live Science readers to see who can ...

The periodic table - AQA Mendeleev made an early periodic table. In the modern periodic table, elements are in order of atomic number in periods and groups. Electronic structures model how ...