Foundations of College Chemistry - Chapter 10 Notes

Electromagnetic Radiation: Energy that travels in waves. Types include radio waves, X-rays, visible light, and microwaves.
Basic Properties of Waves:
- Wavelength (λ): Distance between consecutive wave peaks.
- Frequency (v): Number of wave peaks that pass a point per second.
- Speed of Light (c): All electromagnetic radiation travels at the speed of light.
- Energy of Photons: E = hu = hc/λ where h = Planck’s constant.
Electromagnetic Spectrum: Range of all types of electromagnetic radiation, displaying both wave-like and particle characteristics (photons).

Bohr's Theory:
- Electrons exist in defined orbits around the nucleus at fixed distances.
- Absorption/emission of energy results in transitions between these orbits.
- Each orbit corresponds to a quantized energy level.
Ground State: The lowest energy level of an atom. Energy gaps between levels dictate the emission spectrum.
The hydrogen spectrum can be explained well by Bohr’s model, but it fails for multi-electron systems.

Wave-Particle Duality: Proposed by DeBroglie; matter can exhibit wave-like behavior.
- Schrödinger Equation: Developed in 1926 to describe the wave nature of electrons and calculate probabilities within atoms.
Atomic Structure:
- Shell (n): Energy level of electrons, further divided into subshells and orbitals.
- Subshells Types: s (1 orbital), p (3 orbitals), d (5 orbitals), f (7 orbitals).
- Each orbital can hold 2 electrons with opposite spins (Pauli Exclusion Principle).

Electron Configuration: Arrangement of electrons across shells and subshells, following three main rules:
1. Fill lowest energy orbitals first.
2. Each orbital holds 2 electrons of opposite spin.
3. Degenerate orbitals are half-filled before pairing.
Total Electron Capacity for each shell calculated using the formula: 2n², where n = shell number.
- Example: n=3 holds a maximum of 18 electrons

Periodic Table groups elements based on their valence electron configuration.
- Valence Shell: Outermost shell, influencing chemical reactivity.
- Elements in the same group share similar chemical properties due to similar valence electron configurations.
Valence Electrons: Number corresponds to the group number in the periodic table. Phosphorus (P) has 5 valence electrons (Group 15).
Examples of Electron Configurations:
- Sodium (Na): [Ne] 3s¹ = 11 electrons.
- Argon (Ar): [Ne] 3s² 3p⁶ = 18 electrons.

Problem examples cover calculating the maximum number of electrons in subshells, determining elements based on electron configuration, and writing electron configurations for given elements.

Table of Electron Configurations: Lists the electron configurations of the first few elements, side by side with their atomic numbers and corresponding orbitals.