Question

Could someone please describe the shapes of electron density maps for s and p orbital? And why they're shaped the way they are?

Answer 1

See the illustrations below for the orbital shapes, and a discussion of why these shapes are used.

Explanation:

The `s`-orbital has a spherical distribution centred at the nucleus, meaning that there is no preferred axis. The electron is equally likely to be located in any direction from the nucleus.

The `p`-orbital consists of two "lobes" oriented along a particular axis relative to the nucleus. So, we have a `p_x`-orbital, a `p_y`-orbital and a `p_z`-orbital.

The reason these shapes arise is purely a mathematical calculation. When one solves the Schrodinger equation of the hydrogen atom, the solutions (called wavefunctions, `Psi`) one obtains are the functions that describe these various orbitals. These wavefunctions are complex functions (meaning they involve complex numbers, as well as being mathematically somewhat complicated).

The orbitals represent the probability distribution found by multiplying each wavefunction by its complex conjugate (`Psi`*). So, the orbital is a "map" to describe where electrons are most likely to exist.