Halogens Group properties

Niobium is a soft grayish-silvery metal that resembles fresh-cut steel. It is usually found in minerals with other related metals. It neither tarnishes nor oxidizes in air at room temperature because of a thin coating of niobium oxide. It does readily oxidize at high temperatures (above 200°C), particularly with oxygen and halogens (group 17). When alloyed with tin and aluminum, niobium has the property of superconductivity at 9.25 Kelvin degrees. 

The halogens (group VIIA) of terbium are strong irritants. Most of the compounds are toxic and some are explosive. A vacuum or inert atmosphere must be maintained when working with the metal because of its strong oxidation properties. 

Table 10.4 Benson Group Contributions to Ideal-Gas Properties for Halogen Groups (copied w/ permission—see Ref 8)...

In the halogen group, like in other groups of the periodic table, the heavier elements present more metallic and electropositive properties. It is therefore no wonder that the early observed spedes vdiidi were easiest to be prepared and identified were those containing iodine only. Iodine most readily releases an electron thus stsibilizing iodine cations. In the early studies it was assumed that the iodine cation exists as a mono-atomic one -I. But in later studies this assumption could not be confirmed and it was proven that no monoatomic halogen cations exist instead only polyatomic ones, such as I3,12 were identified. These earlier studies were reviewed by Arotsky and Symons ), whereas the later critics were included in the review by Gillespie and Mor-ton ) and therefore will not be repeated here. 

How does it bond to the halogen group (The halogens bond to nearly every single atom, and so they are often used as a comparison to demonstrate material properties.)... 

Because he was attempting to classify abstract elements, not simple substances, Mendeleev was not misled by nonessential chemical properties. For example, the elements in the halogen group (fluorine, chlorine, bromine, and iodine) appear to be rather different from each other when one focuses on them as isolable simple substances, since they consist of two gases, a hquid, and a sohd, respectively. The similarities among the members of the group are more noticeable when considering the compounds each one forms with sodium, for example, all of which are crystalline white powders.The point is that in these compounds, fluorine, chlorine, bromine, and iodine, are present not as simple substances but in a latent, or essential, form as basic substances. ... 

In the same way, the valence states are -2, 0, 2,4, and 6 in the chalcogen group (O, S, Se, Te, Po) and -1, 0, 1, 3, and 5 in the halogen group (F, Cl, Br, I, At). The number of valence shell electrons is the same for all elements in a group. The number of electrons in a shell or subshell is most important to determine the chemical properties. Missing valence numbers are of interest in electron transfer since single electrons cannot easily be traded between ions of the same element. In this case, the electrons appear in pairs and behave as pairs. 

Occurrence, Uses, and Properties 28-2 Xenon Compounds The Halogens (Group 7A)... 

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