<Tr> <Td> Rubidium </Td> <Td> Strontium </Td> <Td> Yttrium </Td> <Td> </Td> <Td_colspan="13"> </Td> <Td> Zirconium </Td> <Td> Niobium </Td> <Td> Molybdenum </Td> <Td> Technetium </Td> <Td> Ruthenium </Td> <Td> Rhodium </Td> <Td> Palladium </Td> <Td> Silver </Td> <Td> Cadmium </Td> <Td> Indium </Td> <Td> Tin </Td> <Td> Antimony </Td> <Td> Tellurium </Td> <Td> Iodine </Td> <Td> Xenon </Td> </Tr> <Tr> <Td> Caesium </Td> <Td> Barium </Td> <Td> Lanthanum </Td> <Td> Cerium </Td> <Td> Praseodymium </Td> <Td> Neodymium </Td> <Td> Promethium </Td> <Td> Samarium </Td> <Td> Europium </Td> <Td> Gadolinium </Td> <Td> Terbium </Td> <Td> Dysprosium </Td> <Td> Holmium </Td> <Td> Erbium </Td> <Td> Thulium </Td> <Td> Ytterbium </Td> <Td> Lutetium </Td> <Td> Hafnium </Td> <Td> Tantalum </Td> <Td> Tungsten </Td> <Td> Rhenium </Td> <Td> Osmium </Td> <Td> Iridium </Td> <Td> Platinum </Td> <Td> Gold </Td> <Td> Mercury (element) </Td> <Td> Thallium </Td> <Td> Lead </Td> <Td> Bismuth </Td> <Td> Polonium </Td> <Td> Astatine </Td> <Td> Radon </Td> </Tr> <Tr> <Td> Francium </Td> <Td> Radium </Td> <Td> Actinium </Td> <Td> Thorium </Td> <Td> Protactinium </Td> <Td> Uranium </Td> <Td> Neptunium </Td> <Td> Plutonium </Td> <Td> Americium </Td> <Td> Curium </Td> <Td> Berkelium </Td> <Td> Californium </Td> <Td> Einsteinium </Td> <Td> Fermium </Td> <Td> Mendelevium </Td> <Td> Nobelium </Td> <Td> Lawrencium </Td> <Td> Rutherfordium </Td> <Td> Dubnium </Td> <Td> Seaborgium </Td> <Td> Bohrium </Td> <Td> Hassium </Td> <Td> Meitnerium </Td> <Td> Darmstadtium </Td> <Td> Roentgenium </Td> <Td> Copernicium </Td> <Td> Nihonium </Td> <Td> Flerovium </Td> <Td> Moscovium </Td> <Td> Livermorium </Td> <Td> Tennessine </Td> <Td> Oganesson </Td> </Tr> <P> Seven nonmetals exist as diatomic molecules in their standard states: hydrogen (H); nitrogen (N); oxygen (O); fluorine (F); chlorine (Cl); bromine (Br); and iodine (I). They are generally highly insulating, highly electronegative, non-reflective gases, noting that bromine, a liquid, and iodine, a solid, are both volatile at room temperature . Exceptions to this generalised description occur at the boundaries of the category: hydrogen has a comparatively low electronegativity due to its unique atomic structure; iodine, in crystalline form, is semi-lustrous, and a semiconductor in the direction of its layers, both of these attributes being consistent with incipient metallic character . </P>

Name the scientist who is known for classification of metals and non metals