zbentinel

thanks again hermanntrude, your answers have been the best explained and easiest to understand, I have tried giving you more rep but it wont let me until I spread the rep love around a bit more!

Great, thanks for that, so now I just have to look at what follows the word mole, if its of gaseous atoms I know that it mean exactly that, excellent. Thank you all for your help!

Ok then I think im starting to understand this, but is a mole a number of atoms, or a number of particles (protons, neutrons and electrons) within an atom? and does Na(g) mean gaseous sodium? if so, how does one turn Sodium into a gas?

After browsing a few pages looking for a definition of the word Mole I cannot find one which is similar to the last definition I found. Could someone tell me what A Mole is. Also here is a sentence in my chemistry book that uses the word and I don't understand what any of it means. "The first Ionisation Energy of an element is the energy required to remove 1 electron from each atom in 1 mole of gaseous atoms to form 1 mole of gaseous 1+ ions." Also, what's a gaseous atom?

Well I'm not actually in school or college I'm teaching myself from revision books ect out of interest mainly, and so I can go to uni in a few years time and do a degree. But this rule is extremely helpful, as I dont want to just memorise the order Id rather know why its in that order, and that formula explain it perfectly. I have another question now. There are some questions and answers in the revision booklet and one of them is asking me to write down the electronic configuration for Iron. So I put down: Fe: 1s2, 2s2, 2p6, 3s2, 3p6, 4s2, 3d6. The answer booklet told me it was this Fe: 1s2, 2s2, 2p6, 3s2, 3p6, 3d6, 4s2. Now I thought that 4s came before 3d, so why is the electronic configuration written out like this?

This is exactly what I wanted, Thank you very much, now I'll be able to figure things out a hell of a lot easier, and also thank you for pointing out the same value thing.

Hey thanks for the reply. Yeah I read that the 4s energy level is less energetic than the 3d, but 1 I dont understand why, and 2 if anyone knows a link to such a graph with all the energy levels in order thatd be great, because if i want to work out the electronic configuration for say Cerium, id never be able to do it in the correct order due to not knowing which energy levels come where.

Ok im studying just because I want to learn all about well everything,a nd Ive started with some chemistry. Im working through atomic structure at the moment, and i am really puzzled by one part of it, and after browsing the net for ages I cannot find an answer for this. with sub shells I've noticed that the 4s energy level is filled before the 3d energy level, I want to know why this is, and also if there is a formula for working out which energy levels get filled before others. because Having 4s filled before 3d is confusing enough, but when I start getting into the f orbital equations and i think that 4f comes above 5s ect it all gets very tricky for me to work out what goes where. So apart from looking at the periodic table to see what order the shells should fill, are there any other ways I can do it? Im sorry if this isnt clear but its a damn hard question to voice correctly.