Wave behavior: diffraction (bending around obstacles) and interference: in phase → constructive (amplitude adds), out of phase → destructive (cancels). The double slit done with electrons proves matter has wave behavior.
Heisenberg: Δx · mΔv ≥ h/4π (given; no calculations). Pin down position → velocity gets less certain. It is a fundamental limit, not bad equipment, and it is why exact Bohr orbits can't exist.
Schrödinger: Ĥψ = Eψ. ψ (wavefunction) can be + or −. ψ² = probability density.
Total radial probability = probability density × number of points at distance r. Zero at the nucleus, zero at radial nodes, peaks at the most likely distance.
Nodes: total = n − 1 · angular = ℓ · radial = n − ℓ − 1.
Penetration: same n, smaller ℓ has inner bumps near the nucleus → feels more Z_eff → lower energy: ns ‹ np ‹ nd.

Zero points on the r-axis = radial nodes. Count them to identify the orbital: an s orbital has n − 1 (A = 2s, B = 1s, C = 3s above).
Small inner bumps (x) = penetration: probability close to the nucleus, inside inner shells. That's why s electrons feel more Z_eff.
The biggest, outermost peak (z) = most probable distance: it sets the orbital's size. Higher n moves it outward.

Any single orbital (any s, p, d or f, whatever its shape) holds at most 2 electrons; a whole subshell holds 2(2ℓ + 1).
Electrons don't travel along the lobes or trace a figure eight. The picture is a probability region, and Heisenberg says the exact position at an instant is unknowable.
Colors or + / − on lobes are the phase (sign) of ψ, not charge and not energy. The whole orbital has one energy.
Angular nodes = ℓ (planes or cones through the nucleus); radial nodes = n − ℓ − 1.