Quantum Numbers and Electron Configurations

Flashcards covering key concepts from Chapter 1 to Chapter 7 including quantum numbers, orbital shapes, electron configuration rules, and magnetic properties.

What does the principal quantum number $n$ describe about an orbital?

It describes the size of the orbital and how close it is to the nucleus.

What is a collection of orbitals that share the same principal quantum number $n$ called?

A shell.

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

It describes the shape of the orbital.

What orbital shapes correspond to the angular momentum quantum numbers $l = 0$ and $l = 1$?

$s$ orbitals ($l = 0$) are spherical, and $p$ orbitals ($l = 1$) look like dumbbells.

Which letter designations correspond to angular momentum quantum numbers $l = 0, 1, 2, 3$?

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

What is a collection of orbitals with the same $n$ and $l$ values called?

A subshell.

What range of values can the magnetic quantum number $m_l$ take for a given $l$?

$m_l$ can take values from $-l$ to $+l$, including $0$.

If the angular momentum quantum number is $l = 1$, what are all the possible values for the magnetic quantum number $m_l$?

$$-1, 0, +1$$

What are the two possible values for the magnetic spin quantum number $m_s$?

$+\frac{1}{2}$ and $-\frac{1}{2}$

What does the Pauli exclusion principle state?

No two electrons in the same atom can have the same four quantum numbers.

What does the Aufbau principle state?

Electrons fill orbitals starting from the lowest energy level to the highest energy level.

What does Hund's rule state regarding degenerate orbitals?

Electrons will occupy degenerate (equal energy) orbitals individually with parallel spins before doubling up in the same orbital.

What is the ground state of an atom?

The ground state is the lowest energy state of an atom.

What is the key difference between a paramagnetic and a diamagnetic compound?

A paramagnetic compound contains one or more unpaired electrons, whereas a diamagnetic compound has all of its electrons paired.

What is the ground-state electron configuration of a boron atom ($5$ electrons)?

$$1s^2 2s^2 2p^1$$

Why is fluorine ($1s^2 2s^2 2p^5$) classified as paramagnetic?

Because it contains one unpaired electron in its $2p$ subshell.

Why do orbital energies in a hydrogen atom depend only on the principal quantum number $n$?

Because hydrogen has only one electron, so there are no other subshell energy splittings caused by electron-electron interactions.

In multi-electron atoms, which subshell is lower in energy and fills first: $4s$ or $3d$?

The $4s$ subshell is lower in energy than the $3d$ subshell and fills first.