U2S3 Atomic Numbers and Electron Configurations

Vocabulary flashcards covering key terms related to atomic numbers and electron configurations, including quantum numbers, subshells, orbitals, and methods for writing electron configurations.

Angular momentum quantum number (l)

Describes the shape of an orbital.

Aufbau principle

States that electrons fill orbitals in order of increasing energy, building the electron configuration by adding electrons to the lowest available energy levels.

Electron configuration

A representation showing how electrons are positioned in an atom.

Electron spin quantum number (ms)

Describes the spin orientation of an individual electron within an orbital; values are +1/2 or -1/2.

Electron subshell

A set of orbitals with the same principal quantum number (n) and angular momentum quantum number (l).

Hund’s rule

In the ground state, electrons in the same sublevel occupy separate orbitals before pairing to maximize stability.

Magnetic quantum number (m)

Describes the orientation of an orbital in space.

Orbital notation

A diagram that uses lines and arrows to show shells, subshells, and orbitals for electrons in an atom.

Pauli exclusion principle

No two electrons in an atom can have the same four quantum numbers; orbitals can hold at most two electrons with opposite spin.

Principal quantum number (n)

Describes the size of the orbital; n is a positive integer (1, 2, 3, …).

Quantum numbers

The set of numbers (n, l, m, ms) that describe the location and properties of an electron in an atom.

Shell

A group of orbitals with the same principal quantum number (n).

Subshell

A group of orbitals with the same n and l; represented by letters s, p, d, f.

s-subshell

Subshell where l = 0; contains 1 orbital.

p-subshell

Subshell where l = 1; contains 3 orbitals.

d-subshell

Subshell where l = 2; contains 5 orbitals.

f-subshell

Subshell where l = 3; contains 7 orbitals.

Max electrons in s subshell

2 electrons.

Max electrons in p subshell

6 electrons.

Max electrons in d subshell

10 electrons.

Max electrons in f subshell

14 electrons.

2n^2 rule

Total number of electrons that can occupy the nth shell is 2n^2.

Diagonal rule

A method to determine the order in which subshells are filled when writing electron configurations.

Orbital

A region in an atom where an electron is likely to be found; defined by size, shape, and orientation.

Dot structure

A representation showing electrons as dots around the element symbol, indicating distribution in shells.

Orbital shapes and labels (s, p, d, f)

Subshells correspond to shapes: s (l=0), p (l=1), d (l=2), f (l=3).