Summary for Ground-State Electron Configurations and Related Topics

What does the Aufbau Principle state regarding electron configurations?

Electrons fill orbitals in order of increasing energy.

According to Pauli’s Exclusion Principle, how many electrons can occupy an orbital?

Each orbital can hold a maximum of two electrons with opposite spins.

What is Hund’s Rule in relation to electron configurations?

Within the same subshell, electrons occupy separate orbitals with parallel spins before pairing up.

How is electron configuration commonly notated?

Subshells are written with the number of electrons in superscripts, e.g., 1s² 2s² 2p⁶.

When forming cations, which electrons are removed first?

Electrons are removed starting with the outermost shell.

When forming anions, how are electrons added?

Electrons are added to the next available orbital.

Define Effective Nuclear Charge (Z_eff).

The net positive charge experienced by an electron.

What trend does Effective Nuclear Charge exhibit across a period?

It increases across a period due to the addition of more protons.

How does atomic size change across a period and down a group?

Atomic size decreases across a period and increases down a group.

What is the trend in ionic size for cations and anions?

Cations are smaller than their parent atoms, while anions are larger.

Define ionization energy (IE).

Energy required to remove an electron from an atom in the gas phase.

What trend does ionization energy exhibit across a period and down a group?

IE increases across a period and decreases down a group.

What is electron affinity (EA)?

Energy change when an electron is added to a neutral atom in the gas phase.

How does electron affinity trend across a period and down a group?

EA generally becomes more negative across a period and less negative down a group.

What defines electronegativity?

The ability of an atom to attract shared electrons in a bond.

How does electronegativity change across a period and down a group?

Electronegativity increases across a period and decreases down a group.

What is Photoelectron Spectroscopy (PES) used for?

To determine the binding energy of electrons in atoms or molecules.

What information do higher peaks in a PES spectrum indicate?

Higher peaks indicate more electrons in that energy level.

What does the x-axis and y-axis represent in a PES spectrum?

The x-axis represents binding energy, and the y-axis represents relative intensity.