Atomic structure

Updated 05 September 2009, more on the way so keep on looking.

Atoms and atomic structure

NOTE: The diagrams didn't come up here. May be able to sort out the problem later. Out of 20 pages of work, only two pages are displayed here. If you wish for the rest of the work, please email me. These are sample work only.

In the given periodic table (The one I have given) if you observe carefully you will see in each symbol of the element has the above information. Using this information one can write the electronic configuration of an atom or an ion. Look at the valency (actually it is called the oxidation state) but for GCSE purpose you can regard it as the valency. It shows whether it forms a positive ion or a negative ion and if they form the number of charges on it.

This is just an example to understand the periodic table sent to you. On the top right hand corner there is +2 for Magnesium that means it has a valency of 2 only, nothing else. In Sodium it is +1, Potassium +1 or take it as just 1, then all group one elements have a valency of 1 only, all group 2 elements have a valency of 2 only, all group 3 elements have a valency of 3 only. So far so good?

Now look at Carbon, it has +2, +4, -4 as valency. All group 4 elements have +2, +4 or 2 and -4 as the valency. How do they form? I will come back to that problem later on. It is very interesting to see Nitrogen has +1, +2, +3, +4, +5, -1, -2 and -3 as valency. Too early explain but I will come back with examples. Minus valency? That’s correct I’ll come back to it.

The most interesting valency, actually it is called VARIABLE VALENCY is found in transition elements. Most GCE Advanced Level students found this difficult to understand because the way it is explained in books but let me give it in this simple approach.

All transition elements have more than one valency and this is called VARIABLE VALENCY, as simple as that. I am not going to explain it right now, just an introduction only. Is that difficult to understand?

Below is some GCSE work but see how it works.

As a rule all metals form positive ions for example sodium forms a unipositive ions that means positive ions with one plus charge on it.

Similarly Mg forms a dipositive ion, which means ions with two positive charges on it. Sodium becomes a positive ion by losing the outermost electron and this is called ionization. It becomes stable by having eight electrons in the outermost shell. Note all the atoms try and do the same thing that means they all want to be stable; they would do that by having eight electrons in the outermost shell. This is done either by losing one or two even three electrons from the outermost shell. For example Mg, Ca would lose two from the outermost shell so that they have eight in the outer most (New outer most shell).