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Arrangement of Electrons in Atoms. The Quantum Model of the Atom. The Quantum Model of the Atom. Louis De Broglie (1924) Suggested that electrons can have a dual wave-particle nature Confirmed by experiments which showed electrons can undergo diffraction and interference
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Arrangement of Electrons in Atoms The Quantum Model of the Atom
The Quantum Model of the Atom Louis De Broglie (1924) • Suggested that electrons can have a dual wave-particle nature • Confirmed by experiments which showed electrons can undergo diffraction and interference The Observer in Physics Double Slit Experiment and Example in Nature - YouTube
The Heisenberg Uncertainty Principle Werner Heisenberg (1927) • It is impossible to determine simultaneously the position and velocity of an electron • Electrons are detected by interaction with photons (photons have similar energy to electrons and thus alter the position of electrons) Heisenberg's uncertainty – YouTube Quantum Mechanics: The Uncertainty Principle - YouTube
The Schrodinger Wave Equation Erwin Schrodinger (1926) • Developed an equation which treated electrons as waves. • Solutions to the equation (wave functions) give the probability of finding an electron in a given location around the nucleus Atomic orbital– region of space in which an electron is most likely to be found
Atomic Orbitals and Quantum Numbers Quantum Numbers –used to describe the properties of atomic orbitals and the properties of electrons in those orbitals • Three quantum numbers are derived from the Schrodinger equation and indicate energy level, orbital shape, and orbital orientation • One quantum number describes the spin of an electron in an atomic orbital
Principal Quantum Number Principal Quantum Number (n) • Indicates main energy level occupied by an electron. • As “n” increases, energy and distance from the nucleus increases
Angular Momentum Quantum Number Angular momentum quantum number (l) • Indicates the shape of the orbital • Within each energy level, there are sublevels. # sublevels = n
Shapes of Orbitals s – orbital p - orbitals
Shapes of Orbitals d - orbitals
Shapes of Orbitals f - orbitals
Magnetic Quantum Number Magnetic Quantum Number (m) • Indicates the orientation of the orbital around the nucleus
Spin Quantum Number Spin Quantum Number • Indicates the spin of an electron in an orbital Value = + 1/2 or -1/2 • An orbital can hold a maximum of 2 electrons, which must have opposite spin.