CIE simple atomic structure slides

Here you go… A Cambridge powerpoint that covers some of the first few topics.

atomic_structure_presentation[1]

it’s in the “new” pptx format. If you have an older version of powerpoint, you may need to install a converter to read the pptx file (and docx etc files also).. Does anyone have a problem reading pptx files? I imagine you all have the “new” versions of powerproint.

p.s. there are other independent programs out there that can also read them, like the free (And very powerful) OpenOffice

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4 thoughts on “CIE simple atomic structure slides

  1. Hi sir, I have two questions on the e-configuration of atoms.

    1. I understand that the e-configuration for Cr and Cu are different form the others because the energy gap between 4s and 3d subshell is very small and by doing so, the repulsion gets smaller. But how about element such as Si? Si has an e-configuration of [Ne] 3s2 3p2, why not 3s1 3p3? Isn’t the repulsion smaller in the latter case?

    2. According to the chemistry coursebook, the energy gap between 4s and 3d subshell is smaller than the energy gap between 3s and 3p subshell, shouldn’t the gap between 3s and 3p smaller since they are of the same shell n=3?

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    • 1. Yes, the repulsion is smaller for [Ne] 3s1 3p3 than it is for [Ne] 3s2 3p2, but the ‘energy cost’ of having the e- stay in the higher p subshell when there is a lower energy vacancy in the 3s subshell, means that the energy of the [Ne] 3s1 3p3 configuration is overall greater than the repulsion of the two e- in the 3s2.

      It would be like making a stack of bricks, say 6 units tall, but there is no second brick – the position is just a hole, and the other bricks on top of it, just floating above the hole. This would obviously be a high energy situation. A continuous supply of energy needs to be put in to counter the gravitational pull and maintain its position.

      If the 3p subshell somehow fell in energy to the point where it approached the level of the 3s subshell, then the energy of repulsion would eventually be larger than the energy for promotion and the electron would indeed go to a 3s1 3p3 config. But the energy gap is sufficiently large that it normally doesn’t happen. Actually, we can make it happen by supplying the correct energy, but usually this is not an issue we need to consider.

      —–

      2. It doesn’t turn out that way. The beginning of the n=4 shell overlaps or
      ‘cuts into’ the latter stages of the n=3 shell.

      The extent to which this occurs, just happens to leave the 4s and the 3d closer in energy than the gap between the 3s and the 3p.

      Does that help?

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  2. Incidentally, when you put e- in the 3d, the energy of that orbital drops, and then becomes lower than the 4s, which is why from K to Zn, the fist e- lost are ALWAYS from the 4s. e- empty from the highest energy first to the lowest energy last.

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