ionisation energies HELP PLEASE!! AQA AS LEVEL

i do not understand why the shell closest to the nucleus has less shielding, surely the shielding should increase? could somebody please help me to understand this

i do not understand why the shell closest to the nucleus has less shielding, surely the shielding should increase? could somebody please help me to understand this

Electron shielding reduces the attraction between the electrons and the nucleus. In the shell closest to the nucleus, there are no other electron shells between it and the nucleus, so it experiences no shielding. Think of the other electron shells as a kind of barrier. If there are other electron shells in the way, the attractive force between the nucleus and the electrons in your selected shell will be reduced.

How many electrons does Li have?

How many electrons are being removed in your graph?

(My fave answer by a student on mine when asked how many e- Li loses when it reacted said 23!)

it has 4?

Lithium is element number 3 ...

... does this give you a clue?

no I'm confused still

Don't be so ****ing rude.

Let me walk you through this.

Lithium is the third element, atomic number 3, it has three electrons. But in the diagram it clearly implies that seven electrons have been removed. So it cannot be Lithium, it must have at least seven electrons.

Furthermore, the second ionisation energy has a significant increase compared to the first (shown by the steeper line at number 1 which then becomes less steep at number 2). This means that the shell / orbital changes, because orbitals closer to the nucleus experience the force of electrostatic attraction more strongly and require more energy to displace an electron from this force which otherwise holds it in.

Therefore, your element has to have at least seven electrons and must be in the second period. The smallest element on the second period is sodium, Na.