Naked Science Forum
Non Life Sciences => Chemistry => Topic started by: taregg on 19/06/2014 19:29:53
-
can you write these elements up to down ..from more reactive to less reactive
F O N C Cl S P I Br.....
-
can some body answer my question. ...Please
-
You have to define what you mean by "reactive" a little better (reacting with what? under what conditions? do you care about reaction rate, heat of reaction, activation energy?). A simple google search will show the order of electron affinity or electronegativity (all of the elements you listed are likely to gain electrons, when reacted with metals; though C, P and S are also easily oxidized).
Fluorine has the highest electron affinity of any element, and also forms a very small ion (fluoride), so the heat of reaction is extremely high. However, fluorine gas (F2) has a fairly strong bond and is not very polarizable, as compared to bromine or iodine (Br2 or I2), so it can actually be harder to get a reaction started. An additional complication is that Br2 is a liquid, so the concentration of Br2 is much higher than even highly compressed F2, and the higher concentrations usually allow for significantly faster reactions (many metals will spontaneously combust on contact with liquid bromine, but not when exposed to chlorine gas, which one might expect to be more reactive...)
To make matters even more complicated, some of the elements listed (most notably C, P, S and O) exist in many allotropes (different chemical structures, but each composed of only one element). Diamond, graphite and the whole family of fullerenes are all different allotropes of carbon, with (very) different chemical and physical properties. Phosphorus can also exist in several different forms, most notably red phosphorus (more stable) and white phosphorus (extremely reactive). Sulfur is typically found in as a cyclic octomer (S8), but when heated, can form any number of cyclic and acyclic polymers. At high enough temperatures, S2 can be the dominant form--and this is quite reactive. O3 (ozone) is significantly more reactive than oxygen (O2), and can even react with itself and detonate at a high enough concentration and temperature. Even O2 can exist in two electronic different states (not quite different allotropes)--the ground state is paramagnetic (triplet oxygen), but can be excited to form a diamagnetic form (singlet oxygen), which is so reactive that at room temperature, most organic compounds would spontaneously combust in an atmosphere of pure singlet oxygen (and the reaction is diffusion limited).
I hope this helps (or was interesting)