Quantum Theory (Chapter 4)
Quantum Theory Treats electron’s location as wave property Defined by quantum numbers Orbitals have different energies Quantum numbers Provide information about size, shape, and orientation of atomic orbitals Define atomic orbitals from general to specific
Quantum Mechanical Model Opposite charges attract, electrons are attracted to the nucleus of an atom Takes a LOT of energy to keep electrons away from the nucleus. Electrons are found at differing lengths from the nucleus and can only be present in certain locations Some ideas are old.
Principal Quantum Number (n) Determines orbital size and electron energy Same as “n” value/orbital in Bohr model Positive whole number, NOT 0 Shells – orbitals with same value n = 1, 2, 3, 4, etc.
Orbital Angular Momentum Quantum Number (l) Defines orbital shape for a particular region of atom Think of as “subshell” Energy sublevels—within the main energy level s = 1 orbital, can hold 2 electrons p = 3 orbitals, can hold 6 electrons d = 5 orbitals, can hold 10 electrons f = 7 orbitals, can hold 14 electrons
Orbital Shapes s orbital p orbital 1 possible orbital orientation, spherical shape n value determines size Charge cloud found near center, likely electron location p orbital 3 possible orbital orientations, dumbbell shape pX, py, pz
l Orbital/Subshell s 1 p 2 d 3 f
Energy levels and Sublevels
How do you specify orbitals?
Magnetic Quantum Number (ml) Describes orbital orientation within an atom ml = -l to +l (number of orientations)
Ex.1: L = 0 Ml = 0 S shape Can only be in one orientation
Ex. 2: L =1 Ml = -1, 0, 1 p shape 3 possible orientations How many orbitals in p subshell?
Ex. 3: L = 2 ml = -2, -1, 0, 1, 2 d shape/subshell How many orientations? How many orbitals?
Electron Spin Describes the motion of an electron, spinning As electron moves, magnetic field induced Electrons with opposite spins, cancel magnetic field of other Values: +1/2, -1/2
What does atomic structure REALLY look like? P
Homework Complete Quantum Worksheet Read pp. 117-122