Atomic Structure Quick Revision Sheet
Subatomic Particles
- Proton: Positively charged particle found in the nucleus.
- Neutron: Neutral particle found in the nucleus.
- Electron: Negatively charged particle
orbiting the nucleus.
Atomic Terms
- Atomic number (Z): Number of protons in the nucleus.
- Mass number (A): Sum of protons and neutrons in the nucleus.
- Isotopes: Atoms of the same element with different mass numbers (due to varying neutron numbers).
- Isobars: Atoms of different elements with the same mass number.
- Isotones: Atoms of different elements with the same number of neutrons.
Atomic Models
- Dalton's model: Atoms are solid, indivisible spheres.
- Thomson's model: Atom is a positively charged sphere with electrons embedded in it (plum pudding model).
- Rutherford's model: Atom has a small, dense, positively charged nucleus surrounded by electrons.
- Bohr's model: Electrons orbit the nucleus in specific energy levels or shells.
- Quantum mechanical model: Electrons are described by wave functions and probability distributions (orbitals).
Quantum Numbers
- Principal quantum number (n): Specifies the energy level or shell.
- Azimuthal quantum number (l): Specifies the shape of the orbital (s, p, d, f).
- Magnetic quantum number (m): Specifies the orientation of the orbital in space.
- Spin quantum number (s): Specifies the spin of the electron
(+1/2 or -1/2).
Electronic Configuration
- Aufbau principle: Electrons fill orbitals in order of increasing energy.
- Hund's rule: Orbitals within a subshell are filled singly before pairing.
- Pauli exclusion principle: No two electrons in an atom can have the same set of quantum numbers.
Atomic Spectra
- Emission spectrum: Light emitted by excited atoms.
- Absorption spectrum: Dark lines in the spectrum of white light that correspond to the wavelengths absorbed by atoms.
Additional Topics
- Ionization energy: Energy required to remove an electron from an atom.
- Electron affinity: Energy released when an electron is added to an atom.
- Periodic trends: Variations in properties across the periodic table (e.g., atomic radius, ionization energy, electron affinity).
Remember to review examples and practice problems to solidify your understanding.
