lecture 1 atomic structure intro

What does Bohr's model say about electron envergies?

What does Bohr's model say about electron energies?

What does Bohr’s model say about electron energies?

Electrons occupy only certain allowed, quantised energy states

When can an atom absorb or emit energy?

When an electron moves from one allowed energy state to another.

What equation relates photon energy to frequency?

E = hν, where h is Planck’s constant and ν is frequency.

What two types of behaviour do electrons display?

What two types of behaviour do electrons display?

What is a node?

A region where the probability of finding an electron is zero.

What is a wave function, ψ?

An equation used to describe an electron.

What does Heisenberg’s uncertainty principle state?

The position and momentum of an electron cannot both be known precisely at the same time.

What does ψ² represent?

Electron density: the probability of finding an electron at a particular location.

What does the angular momentum quantum number, ℓ, describe?

The shape of the orbital.

What values can ℓ take?

Integer values from 0 to n − 1.

Which subshells correspond to ℓ = 0, 1, 2 and 3?

ℓ = 0 is s, ℓ = 1 is p, ℓ = 2 is d and ℓ = 3 is f.

What does the magnetic quantum number, mℓ, describe?

orientation of an orbital in space.

What values can mℓ take?

−ℓ to +ℓ, including zero.

State the Aufbau principle.

Orbitals are filled in order of increasing energy, with no more than two electrons per orbital.

State Hund’s rule.

Orbitals of equal energy are occupied singly by electrons with identical spins before electrons begin pairing.

What happens to the size of an s orbital as n increases?

It increases in size.