Currently unavailable: for regular students
Degree: Chemistry (MChem, BSc - Integrated Masters) (Masters) - Leeds University
Hello, I’m Daniel and I’m currently a second year student at the University of Leeds, studying for an Integrated Masters in Chemistry. I am friendly, patient and very organised. I particularly enjoy the physical side of Chemistry (topics such as thermodynamics, kinetics and equilibria) as it is methodical and logical which suits my style of working.
In the past I’ve tutored GCSE Chemistry (although, mainly focusing on the calculations due to the individual strengths of my tutee) and taught AS Critical Thinking to a group of 14-15 year olds as part of the extra-curricular subjects offered by my High School. I have also organised and run a number of revision sessions with my own year group at A Level and I have continued to do so at University.
I work with Primary School aged children as well, which has given me much experience with simplifying explanations and has increased my patience and positivity exponentially.
Tutorials will be aimed towards what you struggle with – going over the theory, before testing and cementing knowledge with questions from past papers, revision sites/books or real-life scenarios (to help with scientific exam questions that are becoming increasingly aimed at testing students’ problem solving abilities). This also helps to keep the tutorials engaging.
There will also be a focus on revision – which points are the most important to remember, what topics are most likely to be examined and how the different parts of the syllabus connect together.
Please get in touch if you're interested in finding out more!
|Chemistry||A Level||£20 /hr|
|UKCAT||Uni Admissions Test||790|
The ionisation energy of an element is the energy required to remove the one of the outermost electrons from an atom of the element in its gaseous state.
This is quite a difficult process to measure the energy requirements for however, so it is usually scaled up to the energy required or enthalpy change to remove one mole of electrons from one mole of atoms of an element in the gaseous state, which allows us to measure it in J mol-1 (Energy released per mole). Although, it is much more usual to see kJ mol-1 used, as working in J mol-1 means using some unnecessarily large numbers.
The first ionisation energy is the energy requirement for a single electron to be removed from the uncharged elemental electronic configuration (i.e. for lithium this would be 1s2 2s1) to give a cation with a +1 charge.
This could also be written as a chemical formula: X(g) -> X+(g) + e-, where ‘X’ is a particular element.
If another electron was removed from this cation, to give a new cation with a +2 charge, the process would be referred to as the second ionisation energy and so on.
The second ionisation energy could be represented by: X+(g) -> X2+(g) + e-see more
Two major factors control how tightly held the outermost electron is and therefore how much energy is required to remove it, which gives us the size of the Ionisation energy. The first of these factors is shielding. Electrons in orbitals/shells other than the orbital occupied by the outermost electron repel it slightly, reducing the amount of energy required to ‘pull’ away this outer electron. For example, if we consider Magnesium, which has an electronic arrangement of 1s2 2s2 2p6 3s2 our outermost electron is either of the two from the 3s sub-shell (these are both equivalent to each other) and the two full shells below the 3rd shell will act to shield the outermost electron from the attraction of the nucleus.
The second factor is the effective nuclear charge: the attraction to the positively charged nucleus felt by the negatively charged outermost electron. As the number of protons within the nucleus (i.e. the atomic number) increases, so does the effective nuclear charge.
It may also be worth mentioning the atomic radius (distance between the nucleus and the outermost electron) as this can often be worth a mark on some exam boards. Increased shielding will increase atomic radii, whereas an increase in effective nuclear charge will decrease atomic radii.
We can use these three properties to explain the trend in first ionisation energy:
1st IE decreases down the group: this is because the number of filled shells increases down the group, increasing shielding and the distance between the nucleus and the outermost electrons, for very similar effective nuclear charge. This means the outermost electron is more loosely held down the group and so less energy is required to remove it. Thus, 1st IE decreases down the group.see more