Chemistry question Orbitals

Hi, please can i have help on this question? I dont understand why the answer is d , wouldn’t it be b because there is less spin pair repulsion so the electrons have lower energy and are harder to remove? Here is the question: https://app.gemoo.com/share/image-annotation/594331044995604480?codeId=vz8wx8gbR1Z35&origin=imageurlgenerator

Thank you!

The electrons are held to the nucleus by a force of attraction that is proportional to the product of the charges of the nucleus and the electron and inversely proportional to the square of the distance between them.
The atomic charge increases going across a period left to right and the atomic radius increases. Both of these produce an increasing force of attraction, so the electron removal in group 8 (18) is the most difficult.

Thank you but doesn’t increasing radius produce a decreasing force of attraction because the electrons are further away from the nucleus? Also, can i just count the number of valence electrons i the atom and since there are 8 electrons, it will be hardest to remove an electron because it is stable? Thanks

Sorry, that was careless. The atomic radius DEcreases going left to right across the period.

But how can we tell atomic radius and atomic charge from the orbital diagrams they have given?

You generally can’t. Unless of course you identify the element from the electron-in-box diagram and happen to have the relevant data memorised (don’t try doing this - it is far too much effort) or given to you.

For these types of questions, you should instead focus on identifying which group (and period, if the different options correspond to elements on different periods) the element is in and using the general periodic trends in ionisation energy (i.e elements at the tops of groups have higher ionisation energies than those below, elements to the right of the periodic table generally have higher ionisation energies than those to the left with groups 3 and 6 being exceptions to the first ionisation energy trend) to work out which option has the highest/lowest ionisation energy.