Shapes of s and p orbitals

3 minAS Level1.3.8

AI-drafted, independently checked · not yet teacher-reviewed

By the end of this lesson

By the end you can describe and sketch the shapes of s and p orbitals.

s orbitals are spheres

Every shell has one s orbital: 1s, 2s, 3s, 4s …
Each is spherical, with the nucleus at the centre.
Same shape every time, but bigger as n increases: 2s is larger than 1s, because its electrons are further from the nucleus on average.

p orbitals are dumbbells

From n = 2 upwards, each shell has three p orbitals (there's no 1p).
Each is dumbbell-shaped: two lobes on opposite sides of the nucleus.
The three point along the x, y and z axes, at 90° to each other, so they're called $\text{p}_x$ , $\text{p}_y$ and $\text{p}_z$ .
They have the same shape and energy; only their direction differs.

Quick check

Multiple choiceQuestion 1 · Recall

Which describes the shape of a 2p orbital?

ASpherical, centred on the nucleus.BA flat ring around the nucleus.CDumbbell-shaped: two lobes on opposite sides of the nucleus.DA figure-of-eight path that the electron travels along.

Multiple choiceQuestion 2 · Recall

How does a 3s orbital compare with a 2s orbital?

AIt is the same shape (spherical) but larger.BIt is the same size but a different shape.CIt is dumbbell-shaped, because the third shell is higher in energy.DIt is smaller, because the third shell has more protons attracting it.

Answer the 2 questions above to continue.

Previous lessonShells, sub-shells and orbitals Next lessonWriting electronic configurations

Boundary surfaces: each shape encloses the region where the electron spends most of its time.