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 Dr Quantum - Double Slit Experiment - 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) 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 Orbital Letter Designations and l values l Letter s 1 p 2 d 3 f

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 Magnetic quantum number n l m 1 2 -1, 0, +1 3 -2, -1, 0, +1, +2 4 -3, -2, -1, 0, +1, +2, +3

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.

Atomic Orbitals

Orbital Energy Diagram