Chemistry AS level Question (electronic configuration

Heres the link to the question i need help with Q.4 and the next one down Q9 :

https://resource.download.wjec.co.uk/vtc/2020-21/el20-21_21-10/downloads/lesson4/lesson4-screen5-test-yourself-03-eng.pdf

Reply 1

dbhc2411

For question 4, each arrow represents an electron. The fact one points up and one points down represents 'electron spin'.

The atomic number (i.e. the number of protons/electrons an atom of any element has) is the number of arrows you need to draw.

So ask yourself:
1) How many electrons does a sodium atom have?
2) How many arrows will I need to draw.

The next step is to fill in the boxes. You start by drawing an 'up' arrow in each box in for each orbital (1s, 2s, 2p.. etc), and then fill in the down arrows.
It's been started off for you, the 1s orbital is completely filled, so you move onto the 2s.

It's quite hard to explain by typing, so I would really suggest you take a look at https://www.chemguide.co.uk/atoms/properties/elstructs.html as electron configuration is one of the key fundamentals of all of chemistry.

Similarly, for Q9, if you don't understand the inherent properties of electron configuration for Q4 you'll really struggle with Q9. Take a look at the link!

Simply put, you need to deduce which configuration would take the most energy (i.e. the hardest) to rip an electron away from the atom.

I hope this helps.

(edited 6 months ago)