's' orbitals are spherical around the centre of the nucleus.
'p' orbitals have 'lobes' along x, y, or z axes.
The first four 'd' sub-shells are shaped like a four-leafed clover, on different axes.
The fifth has two lobes with a doughnut shape around the middle.
Spin Pairing
As electrons are both negatively charged, they repel each other like two negative magnets. So that two electrons can both fit into one orbital, they are 'spin paired'.
This means each electron spins in the opposite way to the other, one clockwise and one anti-clockwise. This reduces the effect of repulsion.
However, it is important to note that electrons will only spin pair if they have no other option. If there is a free orbital within the sub-shell, the electron will orbit in this, rather than spin paring.
