AQA A Level Chemistry

Do we need to memorise the values for the 1st and 2nd Ionisation energy of period 3 elements please?Also are there any differences between the 2?

Reply 1

DanielK1456

You aren't required to remeber any specific data values for ionisation energies. However you do need to be aware of the difference between 1st and 2nd. It depends on the element/ion being ionised, but generally the second ionisation energy is larger because the electron is being removed from a positive ion, so there is a greater attraction to be overcome between the negative electron and the positive nucleus. The ratio of postive protons to negative electrons is larger. Large jumps in ionisation energies are seen when electrons begin to be removed from orbitals closer to the nucleus as the smaller distance leads to greater electrostatic attraction. I hope that answers your question :smile:

Reply 2

Philipboi

Original post by anon25x

Do we need to memorise the values for the 1st and 2nd Ionisation energy of period 3 elements please?Also are there any differences between the 2?

You need to memorise the trend, not the values. For example, you need to know why Aluminium's IE1 is lower than Magnesium's. And also why Sulphur's is lower than Phosphorous (as these are exceptions to the general trend of increasing IE1 across the period)