Tennessine 17 in the periodic table, below the five halogens; fluorine, chlorine, bromine, iodine, and astatine, each of which has seven valence electrons with a configuration of . For tennessine, being in the seventh period (row) of the periodic table, continuing the trend would predict a valence electron configuration of , and it would therefore be expected to behave similarly to the halogens in many respects that relate to this electronic state. However, going down group 17, the metallicity of the elements increases; for example, iodine already exhibits a metallic luster in the solid state, and astatine is often classified as
Chlorine pentafluoride with water to produce chloryl fluoride and hydrogen fluoride: It is also a strong fluorinating agent. At room temperature it reacts readily with all elements (including otherwise "inert" elements like platinum and gold) except noble gases, nitrogen, oxygen and fluorine. Chlorine pentafluoride Chlorine pentafluoride is an interhalogen compound with formula ClF. This colourless gas is a strong oxidant that was once a candidate oxidizer for rockets. The molecule adopts a square pyramidal structure with C symmetry, as confirmed by its high-resolution F NMR spectrum. Some of the earliest research on the preparation was classified. It was first prepared by fluorination