SOLVED: Francium, Fr , is thought to be the most reactive of the group 1 alkali metals. However, it is radioactive, has a half-life on the order of minutes, and is available in only small amounts, making it difficult to study. Based on the properties of the other group 1 alkali metals and the periodic trends of these properties, predict the atomic radius, ionic radius of the 1 cation, and the first ionization energy of francium.