Presentation on theme: "Electron Orbitals Cartoon courtesy of lab-initio.com."— Presentation transcript:
1 Electron OrbitalsCartoon courtesy of lab-initio.com
2 The Bohr Model of the Atom I pictured electrons orbiting the nucleus much like planets orbiting the sun.But I was wrong! They’re more like bees around a hive.Neils Bohr
3 Quantum 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…
4 Heisenberg Uncertainty Principle “One cannot simultaneously determine both the position and momentum of an electron.”You can find out where the electron is, but not where it is going.OR…You can find out where the electron is going, but not where it is!WernerHeisenberg
5 Modern Quantum TheoryAs a direct result of Schrondinger’s equation, the first 3 quantum numbers were derived to show properties of –e in specific orbitals in which they are located inThese equations paved the way for quantum theory describing mathematically wave properties of the –e and other small particles
6 First 3 Quantum Numbers describe 1- main energy level2-shape of orbital3- orientation of orbital4th quantum number describes state of –e occupying the orbital (spin number)
7 #1- Principle QN-n (main energy level) Total number of orbitals existing in a shell (energy level) =n2All main energy levels has sublevels (suborbitals) of different shapesValue-positive only- 1, 2, 3… 7-e whose n=1 occupies lowest energy level (closest to the nucleus)
8 Electron 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
9 Electron 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.
10 #2- Angular Momentum-l (shape of orbital) Also known as azimuthal QNFor specific energy level, the number of sublevels possible =nValue of 0 and all positive integers less than or equal to n-1Examples:n=2, 2 shapesl=0 represents sl=1 represents p
11 f- too complicated to discuss More about shapess orbital- n=1- spherep orbital- n=2- dumbelld- complexf- too complicated to discuss
12 s Orbital shape The s orbital has a spherical shape centered around the origin of the three axes in space.
13 p orbital shapeThere are three dumbbell-shaped p orbitals in each energy level above n = 1, each assigned to its own axis (x, y and z) in space.
14 More QN and shapes 1st energy level, n=1- only s orbital 2nd energy level, n=2- only s and p3rd energy level, n=3- s, p and d4th energy level, n=4- s,p,d and f
15 d orbital shapesThings get a bit more complicated with the five d orbitals that are found in the d sublevels beginning with n = 3. To remember the shapes, think of “double dumbells”…and a “dumbellwith a donut”!
17 1 s orbital-spherical only- #3- Magnetic QN-m1 s orbital-spherical only-1 orientation (m=0)3 p orbitals-3 orientations x,y,z(m= -1, m= 0, m= 1)and so on for d and f
18 more 5 d orbitals- orientation has values of m= -2, m= -1, m= 0, m= 1, m=2 representing dx2-y3,dxy, dzy, dxz, dz27 f orbitals-number of orbitals in each energy level equals n2If n=1, n2=1 or if n=3 then n2=9, etc
19 #4- Spin QNValue +1/2 or –1/2Indicates fundamental spin state of the –e (-e spin on axis in one of two directions or states)Spin creates a magnetic field and accounts for the magnetic properties of –e(remember cathode ray and magnet)
20 WRITING QNEach orbital show by its principle QN followed by letter of suborbital1s or 3p or 4d