Fluorine has an atomic number of 9. What can you conclude about an atom of fluorine from this fact?
A number of things can be concluded about the characteristics of an atom, if we know the atomic number of the element in question. In the given case, the element is fluorine and its atomic number is given as 9. The very first thing we can do, is write the electronic configuration of a fluorine atom (containing 9 electrons). The electronic configuration of fluorine is `1s^2, 2s^2, 2p^5`. From the electronic configuration, we can see that fluorine will achieve a noble gas configuration by accessing one more electron. This can be done either by accepting or sharing an electron. In either case, fluorine is a non-metal, since it has a higher tendency to accept electron than donate them. It will have the properties of non-metals. In fact, it is one of the halogen elements, similar to chlorine and bromine, since it requires only one more electron to complete its octet.
Thus, the atomic number has provided us with a lot of information about the atoms of this element.
Hope this helps.
check Approved by eNotes Editorial