#2 Group 17 (halogens) on the Periodic table is the only group which contain elements in all the three phases i.e solid, liquid as well as gaseous phase And they are bad conductors of heat and electricity. #1 Halogens (group 17 elements) are nonmetals. The physical and chemical properties of halogens (group 17 elements) are mentioned below. If any authoritative sources are found further, then this article will be updated) Properties of halogens (Note: Astatine also shows some metallic characteristics. Hence on a newly published Periodic table, astatine is classed as a halogen. (Here is a research work by researchers: condensed astatine)Īlso according to Cotton and Wilkinson, astatine shows more characteristics of halogens. Some researchers have found that pure astatine shows metallic characteristics in condensed phase. (You can get this proof of experiments from google books here)Īll these experiments clearly indicate that Astatine shows behavior similar to that of halogens.īut unfortunately, this is only partially true.īecause it has been found that astatine also forms At + ions in an acidic solution. These experiments concluded that Astatine forms HAt, various salts like LiAt, interhalogens like AtI, and other halogen like bonds. The only way to conduct the experiment is to do so in either gaseous phase or in the dilute solution which absorbs the heat.īut the experiments conducted using such less quantity of elements may not give satisfactory results. And that is why it is very difficult to conduct experiments on it. That means half of the Astatine element will decay in just few hours, which produces heat. The longest half life of a stable isotope Astatine-210 is 8.1 hours and of Astatine-211 is 7.2 hours. Look, first of all the Astatine element is a laboratory made radioactive element.Īnd it has a very short half life. It may or may not be included in the halogen group. Atomic number Symbol Name of elements 9 F Fluorine 17 Cl Chlorine 35 Br Bromine 53 I Iodine 85 As Astatine Is Astatine (At) included in halogens? Here is a complete list of halogens (group 17 elements) of the Periodic table with their atomic number, symbol and name of element. Hence noble gases are chemically inert) List of Halogens
So they do not participate in any chemical reaction. ( Note: Noble gases have even smaller atomic size compared to halogens, but they have complete octet. Thus, fluorine element of group 17 is a highly reactive halogen on the Periodic table. So the electronegativity of fluorine is highest (it has maximum tendency to attract the electrons pair)Īnd because of this, fluorine has a highest tendency to react with any other element to form a compound.Įven fluorine reacts with noble gas like xenon, and forms compounds like XeF4 (Xenon tetrafluoride) and XeF6 (Xenon hexafluoride)
Halogen symbol plus#
In other words, Fluorine is present at the top of the halogen group and it has less atomic size plus it needs only one electron to complete the octet. Now see, the halogens are the most reactive elements, but we know that as we move down the group, the electronegativity decreases (means the tendency to attract the electron pair decreases down the group).
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