Exam Question (module 1) help! plz

Hi, in the image attached i don't understand part 1b) iii

The questions says:

An element X in period 3 of the periodic table has the following successive ionisation energies.

(see image)

Deduce the identity of element X.

Could someone tell me why the answer is Aluminium pleeeeease.

chem.jpg79.8KB

Reply 1

gingerbreadman85

what do you know about ionisation energies?

what electrons will be harder to remove than others?

Reply 2

TheWonderKid

Original post by gingerbreadman85

what do you know about ionisation energies?

what electrons will be harder to remove than others?

I know that ionisation energy increases as electrons are removed (so the 2nd ionisation energy is higher than the first)

And, the further the electrons are away from the nucleus, the lower the ionisation energy because the nuclear attraction is reduced, meaning less energy needed to remove the outer electron. So it would be easier to remove an electron from say, a 3s orbital than a 2p orbital.

Reply 3

gingerbreadman85

Original post by TheWonderKid

So it would be easier to remove an electron from say, a 3s orbital than a 2p orbital.

So, if there is a sudden massive jump between 3rd and 4th ionisation energies, what does this indicate?

Reply 4

TheWonderKid

Original post by gingerbreadman85

So, if there is a sudden massive jump between 3rd and 4th ionisation energies, what does this indicate?

That all the electrons from that energy level have been removed. Aluminium has three in its outer shell which have been removed so now the 4th ionisation energy is going to be REALLY high

I get it now cheers mate. :wink:

Reply 5

gingerbreadman85

Original post by TheWonderKid

That all the electrons from that energy level have been removed. Aluminium has three in its outer shell which have been removed so now the 4th ionisation energy is going to be REALLY high