Nan in Mass Posted May 31, 2009 Share Posted May 31, 2009 I am really stupid about chemistry SIGH. Why are only the electrons in the s and p orbitals valence electrons? Why does hydrogen thave a fairly strong attraction to an additional electron, making it something in group 1 that forms covalent bonds, unlike the rest of the things that tend to form covalent bonds? Do my questions even make sense? Maybe if I understood the why's I could retain the stuff for once. I forget it as fast as I learn it. Now that my youngest is back and we are doing chem again, I find I am having to reread the book from the beginning to have any idea what it is talking about. Last time I looked at it was in Feb. I wish my memory were better. Grrr... -Nan Quote Link to comment Share on other sites More sharing options...
2cents Posted May 31, 2009 Share Posted May 31, 2009 I'll try since we just studied this. As I understand it, electron want to have 8 electrons in the outer shell. If there is anything less than 8 they will steal another. If there are 4 atoms in the outer shell then it is +-4 'valance'. 5 and up the electron will try to get more to complete the 8. Anything less than 4 and the electron will try to get rid of the outer shell and therefore ending up with the next to last as the outer shell (it will already have 8). The number of electrons that an outer shell wants to get or get rid of in order to have a full outer shell is the VALANCE number. Example: An electron with 6 electrons in the shell has a valance of -2 because it wants to steal two to make the total of eight. An electron with 2 in the outer shell will have a valance of +2 because it is easier to get rid of the two instead of stealing 6 more. The outer shell is called the Valance shell. I'm guessing the term 'valance' just refers to it being a cover or outer layer. About the hydrogen...I'm going to have to leave that for now since we're off to see 'UP' but if nobody can help you out in the meantime, I'll see what I can find because I think we read something about that too. Hope this helps! Quote Link to comment Share on other sites More sharing options...
ChemMommy Posted May 31, 2009 Share Posted May 31, 2009 I am really stupid about chemistry SIGH. Why are only the electrons in the s and p orbitals valence electrons? Remember that when you are working with, say, the 4p orbitals, the d-orbitals that are on the same level of the pictured periodic table are ACTUALLY level 3-d orbitals. They belong to the previous shell. So, when we count valence electrons we are looking at the s-orbitals (which would be 4s) and the p-orbitals (that would be 4p) but not the electrons in the 3d-orbitals (which come between the other two). Why does hydrogen have a fairly strong attraction to an additional electron, making it something in group 1 that forms covalent bonds, unlike the rest of the things that tend to form covalent bonds? Not sure I totally understand your question. Hydrogen is in the first level of the table. There are only s-orbitals available, so there are only places to fit in 2 electrons. Hydrogen can either share its electron with something else to make a covalent bond (like in CH4) OR it can transfer its electron as take a positive charge (like in NaH). It makes both kinds of bonds. Quote Link to comment Share on other sites More sharing options...
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