Standard periodic table, element types
Standard periodic table, colour-coded for element types. The periodic table shows the chemical elements ordered by atomic number (number of protons in the nucleus), but arranged in rows (periods) so that elements with similar chemistry occur in the same vertical column (group). Here, blocks of elements with similar chemical properties are shown by the colours identified in the key at bottom. Each element is represented by its chemical symbol. Above each symbol is the element's atomic number, and below it is the element's name, as shown in the labelled example at lower right.
© VICTOR HABBICK VISIONS/SCIENCE PHOTO LIBRARY
Marie Curie, Polish-French physicist
Marie Curie (1867-1934, nee Marya Sklodowska), Polish-French physicist. With her husband Pierre, she isolated the radioactive elements polonium and radium in 1898. Marie won the 1911 Nobel Prize for Chemistry for this work. She had previously been awarded the 1903 Nobel Prize for Physics (with Pierre Curie and Henri Becquerel) for her work on radioactivity. She held the chair of physics at the Sevres Higher Normal School for Girls, working there from 1900-6. Following the death of Pierre in 1906, she became assistant professor at the Sorbonne, Paris, and then full professor in 1908. Photograph by Eugene Pirou, Parisian photographer who was active at the end of the 19th century.
© HUMANITIES & SOCIAL SCIENCES LIBRARY/NEW YORK PUBLIC LIBRARY/SCIENCE PHOTO LIBRARY
Periodic table, computer artwork. This table shows the chemical elements arranged in order of atomic number (the number of protons in the nucleus). Elements with similar chemistry occur in the same group (vertical column). Some groups are colour-coded: alkali metals (yellow, left, except H); alkaline-earth metals (purple with white text); transition metals (blue, centre); other metals (purple with yellow text, centre right); halogens (dark orange); inert gases (yellow, far right). The lanthanide and actinide series of elements (dark blue with white text) are shown in the lower two rows.
© PASIEKA/SCIENCE PHOTO LIBRARY