There’s a radially symmetric blob, and a double-lobed blob with a node in the middle – just like the patterns of electron density that the s and p atomic orbitals give rise to.
The same thing when you're going from filling in the 2 s to putting that first electron into the 2 p.
当你填满，2，s，后再往，2，p，中,放第一个电子的时候就会发生这种问题。
3
So we can think about what is our most loosely-bound electron, what's that highest energy orbital, and it's going to be the 2 p orbital, that's going to be what's highest in energy.