Basics about halogen elements
Halogen elements are truly a very interesting group of elements, that all have relatively similar properties. The chemical side of these compounds is very similar. However, the states they come in under standard conditions vary somewhat. Under temperature of 0°C, and pressure of 100 kPa fluorine (F) comes as a slightly yellow colored gas, chlorine (Cl ) comes as a green colored gas. Furthermore, at standard conditions, bromine (Br) is a dark red to brown colored liquid and iodine (I) comes in the form of dark grey crystals. Thereby, the group of halogen elements is the only group in the periodic table of elements that contains elemenets in form of all three states of matter at room temperature.
In addition to the elements that were mentioned, there is another halogen element that can be found in nature, called astatine (At). However this element is radioactive and has a very short half life, and because of that, it can mostly only be found in traces. Similar to alkali metals, halogen elements are also highly reactive.
The mentioned elements form the group 17 in the periodic table of elements. The reason why halogen elements are so reactive lies in their electron structure. Their outer shell of valence electrons is not full – it needs one more electron to imbibe an ideal electron configuration, what gives these elements a very high tendency to participate in chemical reactions and form new compounds, because that way they release recieve that missing electron (and become negatively charged) and, as already mentioned, thereby they imbibe an ideal electron configuration.
Because of their high reactivity, halogen elements can be found in the nature only in form of compounds or ions. Also, there are substances like halogenated organic compounds that can be found as natural products in living organisms. In their elemental forms, halogen elements exist as simple diatomic molecules, although as it has already been stated, in this state they can’t be found in the nature, but are mostly used in laboratories and industry, where these compounds are required.
Halogen elements also have many other interesting properties. If one is interested in finding out even more about the chemistry of these interesting elements, it’s always a good idea to start with some of the basic lessons related to chemistry.
