Atomic Electron Configurations

The Bohr Model of the Atom I pictured the electrons orbiting the nucleus much like planets orbiting the sun. However, electrons are found in specific circular paths around the nucleus, and can jump from one level to another. Niels Bohr (O.G)

Ernest Rutherford’s Model was a bunch of bunk It did not explain the chemical properties of the elements – a better description of the electron behavior was needed That’s a bunch of crap

The Quantum Mechanical Model In 1926, Erwin Schrodinger created the new model to determine where electrons were located in an atom.

The real atom Organized into energy levels. Denoted with numbers 1-7. As the energy level goes up, the electrons have more energy Electrons found in “clouds” where electrons can be found. Denoted with letters; s, p, d, and f for the shape of the cloud.

1st Rule of electron Filling: Orbitals are filled from the lowest energy up. Copy this mess --> 1st energy level: 2 2nd energy level: 8 3rd energy level: 18 4th energy level: 32 Etc…: 32

s 2 1 1 p 3 6 2 10 d 5 3 7 14 4 f Summary # of shapes (orbitals) Maximum electrons Starts at energy level 2 s 1 1 p 3 6 2 10 d 5 3 7 14 4 f

second rule of electron Filling: No two things can occupy the same space at the same time. The reason why the arrows are drawn one up and one down in the orbital box diagram

Orbital Box Showing electrons in boxes (can also be shown with circles) which represent their energy levels and sublevels Lowest energy first. ? ? Carbon Boron Beryllium Lithium Hydrogen Helium

3rd rule of Electron filling: The most stable arrangement of electrons is that with the maximum number of unpaired electrons. 3 electrons in the 2p orbital would look like Not

Lets practice this junk Use spdf notation and orbital box. B O Ga K Mg

Moar! Li+1 N N-3 Se Ag+1

Now the other way

Noble gas configuration We can use a shortcut to show configurations by using the noble gasses. Instead of filling the whole list, we start at a noble gas and work from there. To do Calcium, we would start from Argon which is 3p6. So calcium would be [Ar]4s2 1s2 2s2 2p6 3s2 3p6 4s2 [1s2 2s2 2p6 3s2 3p6] 4s2 Look at the practice problems we already did together and turn them into noble gas config.

Summarize what you learned What did you learn about electrons this lecture? What are the two models of the atom and how are they different? Summarize on your own.