What is ionisation energy?🤨
Ionisation energy is the energy required to remove 1 mole of electrons from 1 mole of gaseous atoms to form 1 mole of gaseous ions.👇🏼

✹3 important points about ionisation energy in A2/A-Level Chemistry✹
1.Distance
The distance between the nucleus and theouter electrons will affect the ionisation energy. The greater the distance the lower the ionisation energy.
2.Nuclear charge
When there are more protons in the nucleus,the nuclear charge will be higher, and so there will be more attraction. This means the electrons will be more strongly attracted to the nucleus. When the nuclear charge is higher, the attraction will be stronger.
3.Shielding
When there are more inner shells, the outershells do not get as much attraction to the nucleus, because the inner shellsof electrons steal the attraction. This means that the more inner shells there are, the lower the ionisation energy.
Why does ionisation energy across the period increase? 🤔
- The nuclear charge increases so that there is more attraction.
- The outer electrons are all in the same shell so no extra shielding.
- The distance is also the same, so the nuclear charge increases overall.
- More energy needed to remove an electron from outer shell.

Some questions about cation, anion and atom in A2/A-Level Chemistry 🥴
Why is a cation smaller than it’s atom?
There are less electrons than protons and 1 less subshell has been filled.
Why is an anion larger than it’s atom?
There are more electrons than protons and 1 more subshell has been filled.
That's the end of ionization energy.

Drafted by Yoko Mak (Chemistry)
Photo references:
http://www.quickmeme.com/meme/3qmpjf