Andreas von Antropoff his Periodic Table in the article ""Eine neue Form des periodischen Systems der Elemente"" in the "Zeitschrift für angewandte Chemie" in 1926. The periodic table is regularly numbered from 1 - Hydrogen to 118 - Oganesson, with "each number representing the number of protons stored within an atom's nucleus in a satisfying balance" compared to most other contemporary tables. In addition he placed the theoretical "Element zero", which had "been a matter of conjecture for nearly a century" atop his periodic table and called it Neutronium. His periodic table was in widespread use in German schools until 1945 and soon
Extended periodic table have a metallic radius of only 158 pm, very close to that of the much lighter magnesium, despite its expected atomic weight of around 474 u which is about 19.5 times the atomic weight of magnesium. This small radius and high weight cause it to be expected to have an extremely high density of around 46 g·cm, over twice that of osmium, currently the most dense element known, at 22.61 g·cm; unhexquadium should be the second most dense element in the first 172 elements in the periodic table, with only its neighbor unhextrium (element 163) being more dense (at 47