Wavefunction: Schrodinger’s equation is a way to see the trajectory of light as a wave.

Probability Density:
Schrodinger’s equation SQUARED.
The probability that an electron will be found in a small region of volume.

A location where the electron WON’T travel, aka the wavefunction = 0
If an electron is “in-between” two energy levels, then it’s a node cause it is impossible, so the energy level is 0

Angular Nodes:
Between lobes
(Just the l-value)

Radial nodes:
The nodes between energy levels
(n – l – 1)

Allowed in One-electron systems like Hydrogen:
One-electron just means it has one electron, like hydrogen, helium ion, or lithium-ion with 1+ and 2+
Z = Atomic number, so for Hydrogen, it would just be 1
n = Energy level
R = Rydberg’s Constant
h = Planck’s Constant

Why is energy NEGATIVE:
Energy is negative because they are compared to the energy of a free electron.
This means how much ENERGY is needed to POP-OFF an electron.