Quantum Mechanics

What does the wavefunction (Ψ) describe?

The movement of a particle.

What is probability density (Ψ²)?

The probability of finding the particle in a region.

Where is a node located?

Where the probability of finding an electron is zero.

How many nodes do wavefunctions have?

Wavefunctions have (n-1) nodes.

What can an electron do at a node?

An electron can never be at a node, but can 'cross' nodes as they are delocalized standing waves.

For which energy levels do s orbitals exist?

For all energy levels n ≥ 1.

What is the angular momentum quantum number (l) for s orbitals?

L = 0.

For which quantum number do p orbitals exist?

Exists for n ≥ 2.

What is the angular momentum quantum number (l) for p orbitals?

L = 1.

For which quantum number do d orbitals exist?

Exists for n ≥ 3.

What do penetrating orbitals refer to?

Orbitals with radial probability closer to the nucleus.

What is the difference between paramagnetism and diamagnetism?

Paramagnetism has unpaired electrons and is drawn towards magnets; diamagnetism has paired electrons and is slightly repelled by magnets.

What does the principle quantum number (n) define?

The size and energy of the orbital.

What is the allowed value for the principle quantum number (n)?

Must be positive whole numbers.

How do you calculate the number of orbitals in a shell?

Using the formula n².

What does the angular momentum quantum number (l) define?

The 3D shape of the orbital.

What are the possible values for the angular momentum quantum number (l)?

Any integer from 0 to (n-1).

What does the magnetic quantum number (ml) define?

The spatial orientation of the orbital.

What are the allowed values for the magnetic quantum number (ml)?

From -l, …, 0,... +l.

How many spatial orientations are there of orbitals in a subshell?

2l + 1.

How many electrons can an s sublevel hold?

2 electrons.

How many electrons can a p sublevel hold?

6 electrons.

How many electrons can a d sublevel hold?

10 electrons.

How many electrons can an f sublevel hold?

14 electrons.

What does the spin quantum number (ms) define?

The spin axis of an electron.

What are the allowed values for the spin quantum number (ms)?

+½ or -½.

How many electrons are allowed per orbital?

Only two electrons are allowed per orbital.