Light, Photons, and Quantum Orbitals: Physics and Spectroscopy

What is light?

An electromagnetic wave.

What are the properties of light?

Wavelength, frequency, and speed.

What happens as wavelength decreases?

Frequency increases and energy increases.

What is the order of the visible spectrum?

Red → Orange → Yellow → Green → Blue → Violet.

Which color has the lowest energy?

Red.

Which color has the highest energy?

Violet.

What is a photon?

A tiny packet of light energy.

What are the equations for photon energy?

E = hν or E = hc/λ.

What determines photon energy?

Frequency (or wavelength).

What does intensity change in light?

Number of photons.

What are the energy levels of hydrogen?

Electrons can only be in specific levels: n = 1, 2, 3...

What is the emission spectrum?

Electron falls down, releases energy, colored lines appear.

What is the absorption spectrum?

Electron jumps up, atom absorbs specific colors, dark lines appear.

What happens to white light through hydrogen gas?

Produces a rainbow with dark lines.

What does a larger jump in electron energy mean?

Higher-energy light and shorter wavelength.

What is the purpose of the Rydberg equation?

To find the frequency of emitted/absorbed light for hydrogen.

What happens when an electron moves closer to the nucleus?

Energy is released.

What happens when an electron moves away from the nucleus?

Energy is absorbed.

What is the de Broglie wavelength formula?

λ = h/(mv).

Which objects have bigger wavelengths?

Light and small, slow particles.

Which objects have tiny wavelengths?

Heavy or fast objects.

Why do electrons act wave-like?

They have small mass, resulting in relatively large wavelengths.

What is the uncertainty principle?

You cannot know exact position and exact momentum at the same time.

What happens if you know position more precisely?

Momentum becomes less certain.

How do electrons behave under uncertainty?

They exist as fuzzy probability clouds.

How do electrons act in terms of wave patterns?

They form 3D patterns called orbitals.

What are the four quantum numbers?

n = energy level; l = shape; m_l = orientation; m_s = spin.

What is the shape of s and p orbitals?

s = sphere; p = dumbbell.

What is a node?

A place where the electron can never be.

What is the formula for total nodes?

Total nodes = n − 1.

What is the formula for angular nodes?

Angular nodes = l.

What is the formula for radial nodes?

Radial nodes = n − 1 − l.

How many nodes does a 2s orbital have?

1 radial node, 0 angular nodes.

How many nodes does a 2p orbital have?

0 radial nodes, 1 angular node.

What determines hydrogen orbital energies?

Energy depends only on n.

What is true about multi-electron orbital energies?

Energy depends on n and l due to shielding/repulsion.

Which orbital is lower in energy in multi-electron atoms?

2s is lower than 2p.

What does 'degenerate' mean?

Orbitals with the same energy.

Which orbitals are degenerate?

2px, 2py, 2pz.

Which orbitals are degenerate only in hydrogen?

2s and 2p.

What wavelengths does hydrogen absorb?

Those for n=1→2, n=2→3, n=2→4, etc.