Presentation on theme: "Electron Orbitals Cartoon courtesy of lab-initio.com."— Presentation transcript:
1Electron OrbitalsCartoon courtesy of lab-initio.com
2Quantum Mechanical Model of the Atom Mathematical laws can identify the regions outside of the nucleus where electrons are most likely to be found.These laws are beyond the scope of this class…
3Heisenberg Uncertainty Principle “One cannot simultaneously determine both the position and momentum of an electron.”The more certain you are about where the electron is, the less certain you can be about where it is going.The more certain you are about where the electron is going, the less certain you can be about where it is.WernerHeisenberg
4Quantum NumbersEach electron in an atom has a unique set of 4 quantum numbers which describe it.Principal quantum numberAngular momentum quantum numberMagnetic quantum numberSpin quantum number
5Electron Energy Level (Shell) Generally symbolized by n, it denotes the probable distance of the electron from the nucleus. “n” is also known as the Principle Quantum numberNumber of electrons that can fit in a shell:2n2
6Electron OrbitalsAn orbital is a region within an energy level where there is a probability of finding an electron.Orbital shapes are defined as the surface that contains 90% of the total electron probability.The angular momentum quantum number, generally symbolized by l, denotes the orbital (subshell) in which the electron is located.
7s Orbital shape The s orbital (l = 0) has a spherical shape centered aroundthe origin of the three axes in space.
8p orbital shapeThere are three dumbbell-shaped p orbitals (l = 1) in each energy level above n = 1, each assigned to its own axis (x, y and z) in space.
9d orbital shapesThings get a bit more complicated with the five d orbitals (l = 2) that are found in the d sublevels beginning with n = 3. To remember the shapes, think of “double dumbells”…and a “dumbellwith a donut”!
14Electron SpinThe Spin Quantum Number describes the behavior (direction of spin) of an electron within a magnetic field.Possibilities for electron spin:
15Pauli Exclusion Principle Two electrons occupying the same orbital must have opposite spinsWolfgangPauli
16Element Configuration notation Orbital notation Noble gas Lithium1s22s1____ ____ ____ ____ ____1s s p[He]2s1Beryllium1s22s2[He]2s2Boron1s22s2p1[He]2s2p1Carbon1s22s2p2[He]2s2p2Nitrogen1s22s2p31s s p[He]2s2p3Oxygen1s22s2p4[He]2s2p4Fluorine1s22s2p5[He]2s2p5Neon1s22s2p6[He]2s2p6
17Exclusion Warning!Assigning quantum numbers to electrons has been exluded and will not be tested!The following slides are purely for your entertainment
18Assigning the NumbersThe three quantum numbers (n, l, and m) are integers.The principal quantum number (n) cannot be zero.n must be 1, 2, 3, etc.The angular momentum quantum number (l ) can be any integer between 0 and n - 1.For n = 3, l can be either 0, 1, or 2.The magnetic quantum number (ml) can be any integer between -l and +l.For l = 2, m can be either -2, -1, 0, +1, +2.
19Quantum numbers for the first four levels of orbitals in the hydrogen atom Orbital designationml# of orbitals11s22s2p-1, 0, 133s3p3d-2, -1, 0, 1, 2544s4p4d4f-3, -2, -1, 0, 1, 2, 37