Ionisation energy

Jiemanutz SG

From what i know, the I.E of an element increases across the period and decreases down the group. But can anyone enlighten whether this theory applies to only first I.E or any number I.E? and how do we determine which group does an element belongs to just by seeing their 3rd I.E

dkcx SG

If you are given a list of IE, the IE will keep dropping. However if u see a sudden and large surge in IE, that means that its removing an electron from the previous shell filled with electrons.

IE1 is 300, IE2 is 50000, IE3 is 500

This means that this is a group 1 element cos it requires little energy to remove the electron but IE2 is very large which shows that its removing an electron from a previous shell liao.

Do note that filled subshells also requires slightly more energy to remove an electron so for eg, 5 electrons, 2 in s orbitals, 3 in each of the 3 p orbitals will require slightly more energy to remove since partially filled shells are relatively stable as well.

So starting from group 8, the 1st IE for removing the 8th electron will be very large and it will be much lower for removing the 7th, lower for the 6th, rise for the 5th cos its partially stable, lower for 4th, lower for 3rd, slight rise for 2nd, lower for 1st.