Unit 2: Atomic Structure
Understanding the structure of atoms is fundamental to chemistry and physics. This chapter covers the history and discovery of atomic structure, including subatomic particles and isotopes. It explains electron configurations and energy levels, as well as spectroscopic evidence that reinforces atomic models.
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2.7.2Slater’s Rules For Estimating Z_eff
Slater's Rules provide a systematic way to estimate the effective nuclear...
What we have learnt
- Atoms consist of protons and neutrons in a nucleus with electrons in quantized energy levels around them.
- Isotopes are variants of elements with the same number of protons but differing numbers of neutrons, affecting their mass and stability.
- The quantum mechanical model describes the behavior of electrons in atoms using wavefunctions and quantum numbers.
Key Concepts
- -- Subatomic Particles
- Atoms are composed of protons, neutrons, and electrons, each with distinct masses and charges.
- -- Isotopes
- Atoms with the same atomic number but different mass numbers due to varying neutron counts.
- -- Effective Nuclear Charge (Z_eff)
- The net positive charge experienced by an electron in a multi-electron atom, accounting for shielding by other electrons.
- -- Quantum Mechanical Model
- The modern understanding of atomic structure, where electrons are found in orbitals defined by quantum numbers.
- -- Aufbau Principle
- Electrons fill the lowest energy orbitals first before occupying higher energy levels.
- -- Pauli Exclusion Principle
- No two electrons in an atom can have the same set of four quantum numbers.
- -- Hund's Rule
- Electrons will fill degenerate orbitals singly and with parallel spins before pairing.
- -- Emission and Absorption Spectra
- The distinct lines observed in atomic spectra are due to transitions between quantized energy levels of electrons.
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