# Atomic Structure - Shapes of S and P orbitals AQA a level chem

Can someone please explain how these shapes work to me please and do we need to know the actual shape for this exam board. also is there any reason for why the x axis doesn't have a line for some of them and why the line is faint on some?
(edited 2 months ago)
Hi there!

Essentially the orbital shapes represent where an electron is most likely to be found at any point in time around the nucleus of an atom (only being approximations). It's possible you might have to be able to recognise them but it seems unlikely to come up, and I don't think you'll ever be asked to draw them. Overall I would say focus on understanding electronic structure of atoms - this is much more important

As for the lines my guess would be it's just a formatting thing
Original post by Rohan007best
Can someone please explain how these shapes work to me please and do we need to know the actual shape for this exam board. also is there any reason for why the x axis doesn't have a line for some of them and why the line is faint on some?
Orbitals were determined by quantum mechanics.
What you need to know are: orbitals are filled from the lowest energy level, orbitals hold 2 electrons with opposite spins, for orbitals at the same energy level you fill each one with an electron before pairing.
Sub-shell - group of orbital of same type.
S subshell (contain a S orbital), P subshell (contain 3 p orbitals), d subshell (contain 5 d orbitals).
For the shapes - you need to know s and p. S is spherical, P is dumbbell.
Order is 1s -> 2s -> 2p -> 3s -> 3p -> 4s -> 3d -> 4p, based on energy level.
Exceptions are Cu and Cr, who have 4s1 -> 3d10 and 3d5.

For the axis in your questions, all the axis should be present, who ever made the image, decided on not using consistent lines for the axis.
Original post by BankaiGintoki
Orbitals were determined by quantum mechanics.
What you need to know are: orbitals are filled from the lowest energy level, orbitals hold 2 electrons with opposite spins, for orbitals at the same energy level you fill each one with an electron before pairing.
Sub-shell - group of orbital of same type.
S subshell (contain a S orbital), P subshell (contain 3 p orbitals), d subshell (contain 5 d orbitals).
For the shapes - you need to know s and p. S is spherical, P is dumbbell.
Order is 1s -> 2s -> 2p -> 3s -> 3p -> 4s -> 3d -> 4p, based on energy level.
Exceptions are Cu and Cr, who have 4s1 -> 3d10 and 3d5.
For the axis in your questions, all the axis should be present, who ever made the image, decided on not using consistent lines for the axis.
hi, perfect thanks so I know all of which u mentioned including s being spherical and p being dumbells but in terms of the diagram do I need to memorise and be able to draw that?
Original post by Methene
Hi there!
Essentially the orbital shapes represent where an electron is most likely to be found at any point in time around the nucleus of an atom (only being approximations). It's possible you might have to be able to recognise them but it seems unlikely to come up, and I don't think you'll ever be asked to draw them. Overall I would say focus on understanding electronic structure of atoms - this is much more important
As for the lines my guess would be it's just a formatting thing

hi is there a reason for why the p orbitals dumbbell shapes are in 3 different directions like what is the science I need to know behind that?
Original post by Methene
Hi there!
Essentially the orbital shapes represent where an electron is most likely to be found at any point in time around the nucleus of an atom (only being approximations). It's possible you might have to be able to recognise them but it seems unlikely to come up, and I don't think you'll ever be asked to draw them. Overall I would say focus on understanding electronic structure of atoms - this is much more important
As for the lines my guess would be it's just a formatting thing

hi is there a reason for why the p orbitals dumbbell shapes are in 3 different directions like what is the science I need to know behind that? Also why is one spherical? ANd y is the y axis like that in a normal graph the y axis would be where z is right?
Original post by Rohan007best
hi is there a reason for why the p orbitals dumbbell shapes are in 3 different directions like what is the science I need to know behind that? Also why is one spherical? ANd y is the y axis like that in a normal graph the y axis would be where z is right?

1.

That's just the way the electrons are distributed. I won't pretend to know why exactly it makes that shape but you would never need to know the reason for A-levels.

2.

The spherical orbital is the s-orbital.

3.

By convention mathematically the z axis points upwards. Imagine a 2D object lying in front of you - that shows you the x and y axes. Then to make it 3D you add depth upwards.

Original post by Methene

1.

That's just the way the electrons are distributed. I won't pretend to know why exactly it makes that shape but you would never need to know the reason for A-levels.

2.

The spherical orbital is the s-orbital.

3.

By convention mathematically the z axis points upwards. Imagine a 2D object lying in front of you - that shows you the x and y axes. Then to make it 3D you add depth upwards.