Electron images

Scientists working for IBM Research in Zurich have released images showing the charge distribution in a single molecule (click here for the image). The scientists have managed to image how the electron charge is redistributed throughout a molecule when bonds form between atoms. The image is computer generated but is interesting all of the same. It relies on a technique called 'Kelvin Probe Microscopy' - which essential relies on a tiny probe which 'feels' its way over the molecule (perhaps, unsurprisingly, this is a ...

Pink Diamonds

A news article on the BBC website (click here to read it) caught my eye yesterday. It was about the largest pink diamond ever mined. Without wanting to get into the nitty gritty of how much it is worth, how many carats it is, etc,  I thought I would focus today's posting on diamonds and what it is that makes them pink (and other colours). Unfortunately, from the chemical point of view, pink diamonds (and red, purple or brown diamonds) are quite ...

Topic 3: Periodicity – Trends in the Frist Ionisation Energies

Perhaps the most important part of the periodicity topic is the the trends and patterns in first ionisation energies both down a group and across a period. This is found under section 3.2.2 and 3.2.3 of the syllabus. It builds on the ideas we covered yesterday - namely, the electron arrangement in the atom, as well as shielding of the outer electrons by the inner shells, the distance of the outer electrons from the nucleus and the number of protons in ...

Topic 3 – Periodicity – Trends in the Atomic Radii

Yesterday I dealt with electronegativity. Once your students are secure in this concept, you will be able to expand upon your teaching of this topic. Section 3.2.2 and 3.2.3 of the syllabus deals specifically with trends both across period 3 and down group 1 and 7. In order to understand the concepts involved, your students will need to be familiar with the electron arrangement in atoms and the concept of shielding (of outer shell electrons by inner shells), as well as the ...

Electrongeativity

To effectively teach topic 3.2 (Physical trends) of the Periodicity unit, you need to introduce the students to the concept of electronegativity. In order to assist your teaching, the following video may help. You should also emphasize to the students that electronegativity is only found in covalent bonding (and not the common misconception, that it is found in all bonds). OgAEnuYKcPg

Periodicity – Topic 3 and 13

This follows on from yesterdays posting - just a couple of ideas for labs work you could carry out when teaching this topic. I should stress that this is only a list of ideas / suggestions and that if you intend using any of these ideas to assess for IA, please ensure that they are given to the students in the appropriate format. Discuss similarities and differences between elements in the same group - this lends itself to a lab on ...

Periodicity: Topic 3 and 13

If you are a May session school, it is very likely that by this point in time you will have finished and you may wish to use it yourself to revise or just share it with your students. It does not cover everything but is a good starting point. To download the powerpoint, click on the file below: pt_trends Many thanks to the website www.ibchem.com for providing this.  

Watching Electrons in H+

When atoms react, electrons are exchanged. Now, a team from Goethe University, Frankfurt, Germany have revealed movie footage of the movement of electrons. The amazing thing about the process is the speed at which the electrons move. The process is measured in attoseconds - one attosecond is a billionth of a billionth of a second. In order to 'watch' this movement of an electron, H+ (or the molecular hydrogen ion) is used. H+ is used as it is the simplest molecule - ...