C3L6 rotational symmetry question

Hi, I'd appreciate any help on the following 2011 C3L6 question:
Screenshot 2023-09-09 012837.png

mark scheme:
Screenshot 2023-09-09 012740.png

I'm not sure how the top right structure has no rotational symmetry. I've tried to illustrate how I'd rotate it 180 degrees so it becomes the same structure. I also don't see how the 3 structures below it have rotational symmetry, I would've drawn all the structures in the vertically opposite boxes

Reply 1

bl0bf1sh

Original post by Reuben C

Hi, I'd appreciate any help on the following 2011 C3L6 question:
Screenshot 2023-09-09 012837.png

mark scheme:
Screenshot 2023-09-09 012740.png

Do you have a model kit? Or some blu tack and some pins? I find it really helps to work things out!

I’ve drawn it out, where light green = plane of symmetry (think mirror), and light blue = rotational symmetry axis (think spinning it round on a stick)

Starting with the bottom right:

Spoiler

Bottom left:

Spoiler

And top right:

Spoiler

Does that help at all?

Tried to upload some videos but TSR was having none of it… if you'd like them let me know and I'll see if I can sort something :smile:

(edited 7 months ago)

Reply 2

Reuben C

Ahh I get it, thank you so much! I think I was too fixated on the drawing of the structure on paper instead of picturing the 3D shape of the tetrahedral carbon atoms. Thanks for the tip, I'll be sure to model any problems in the future :smile: