Who are you?
I'm a chemistry student at Durham University who has a (slightly nerdy) passion for not just chemistry but all things science. During my A-levels I really got gripped by how interesting studying the natural world is, and just how useful it becomes to us in everday life!
Why do you want to tutor?
Because of that interest, I really want to pass on what I've learnt to others who are studying science (partiularly chemistry) and hopefully give you a similar fascination with the material you're looking at in your course. I have had a lot of experience with primary age kids on holiday camps, so my patience is almost limitless, and the energy needed for the younger children I will put into the sessions to make them fun and engaging, as well as helping you to understand what's going on in the science.
If this sounds good to you, give me a message or book a free 'meet the tutor' session where you can get a good impressions of what the sessions will look like and whether you want to go ahead with them.
Thanks for reading and I look forward to hearing from you!
|Chemistry||A Level||£20 /hr|
Samia (Student) January 28 2016
Ryan (Student) April 7 2016
White light is a mixture of different colours of light (e.g red, green and blue) and each colour has a different wavelength. For something to have colour, it needs to absorb certain wavelengths (or colours) of light. What's left over is what we see. So how do transition metals do that?
When they dissolve in solution, they don't exist as isolated ions but are surrounded by ligands (in aqueous solutions they're water molecules). These ligands donate a pair of electrons to the positive metal ion in a dative covalent bond. For example, iron forms [Fe(H2O)6]2+ which is pale green. These ions are called complex ions.
All transition metals have electrons in their d orbitals, which are electrostastically repelled by those donated by the ligands. Since d orbitals have different shapes and orientations, they're not all repelled to the same extent: for an octahedral complex ion, the ligands are placed at the 6 corners of the octadedron. The dz2 and dx2-y2 are pointing to those corners and so are repelled a lot. The other three d orbitals don't point directly towards the ligands and so are repelled less. Therefore, the dz2 and dx2-y2 orbitals are at a higher energy than the other three, and so an energy gap is created, called d orbital splitting.
When light shines on the solution, wavelengths of light that have an energy equal to the energy gap between the two sets d orbitals take electrons in the lower energy orbital to one at the higher energy level. The wavelengths left behind are what we see!