Unpaired electrons

[EvaLi_3J]

Can anybody please explain what unpaired electrons are? When would there be unpaired electrons?

[Izzie Capra 2E]

Unpaired electrons are electrons that fills an orbital alone; it doesn't have another electron to provide opposite spin. It's best to think about this when you are drawing arrows to represent the electrons filling orbitals.

For example,

C: (atomic number =6)

2p _ _ _
2s _
1s _

Since there are 6 electrons, there will be 2 in 1s. There will also be 2 in 2s, each having an opposite spin because one arrow points up and one points down. However in 2p, you fill in 2 up arrows before you write any down arrows, so these electrons will be unpaired (they have parallel spin).