<human>:  Can you tell me about the periodic table of elements?
<bot>: The periodic table of elements is an organized chart where all of the known elements are arranged in order of their atomic number. It was first developed in the 1800s by Russian chemist Dmitri Mendeleev. In the table, elements are grouped in columns according to similar properties. Each element is identified by its atomic symbol and atomic number. The elements are also divided into metals, nonmetals, and metalloids depending on their properties. The elements in the table can be used to help predict the properties of other elements, and are often used to develop new substances and technologies.