
Chapter 6
Equations to know:
E = hν (Energy is equal to Planck’s constant, h, times frequency, ν, of radiation – will not need to memorize h)
c = λν (Speed of light, c, equals wavelength, λ, times frequency, ν  you should memorize the speed of light, c = 3.00 * 108 m/s

Know that the photoelectric effect is the ejection of electrons by a metal when struck with light of sufficient energy
 As atoms increase in atomic number (# protons) they increase in the number of electrons likewise and it has been demonstrated that it is not possible to know accurately the position and momentum of an electron (Heisenberg Uncertainty Principle). Due to this we describe the location of the electrons in a statistical approach that was described by the Schrodinger wave function squared and led to the quantum numbers to describe the electrons.
 Know the names and meaning of the quantum numbers which describe the electrons in an atom

ch 6
Principal Quantum Number, n, tells us the energy level of the electrons and has values of n = 1,2,3, 4,etc
 Angular Momentum Quantum Number, l, sometime called azimuthal quantum number tells us the shape of the orbital. Each orbital can hold 2 electrons.
 It has values of l = 0 to n1
 l = 0 signifies s orbital (spherical shaped orbital)
 l = 1 signifies p orbital (dumbbell shaped orbital)
 l = 2 signifies d orbital (multiple shapes of orbitals)
 l = 3 signifies f orbital (multiple shapes of orbitals)


Magnetic quantum number, ml, tells us the position of axis along which the orbital is aligned, e.g. for p orbitals whether it is on xaxis, px, yaxis, py, or zaxis, pz. It has values of –l to +l ; for example in a 3d subshell (or any other d subshell) there are 5 ml values of 2, 1, 0, +1, +2


All the above quantum numbers came from the Schrodinger equation. Later the need was recognized for the 4th quantum number called the magnetic quantum number, ms, which distinguishes between the 2 electrons in an orbital. ms can have values of either +1/2 or 1/2 to represent the two electrons that have opposite spin.


Know how to write a complete electron configuration for any element as well as a condensed electron configuration for each element (i.e. use of the last noble gas to shorthand the electron configuration).


Know the Pauli Exclusion Principle (no two electrons can have the same 4 quantum numbers) and Hund’s Rule (electrons fill orbitals to minimize repulsions, i.e. fill the different orbitals with a single electron in each orbital at a given energy level before having 2 electrons together in a single orbital). Be able to identify electron configurations that break these rules.

