COULOMB’S LAW (POTENTIAL ENERGY FORM)
• q1 and q2 are the charges of the particles
• r is the distance between particles
• U = 0, the particles have no net interaction with each other• +U, the particles have a net repulsive interaction.• -U, the particles have a net attractive interaction.
REVIEW OF ELECTROMAGNETIC RADIATION
• c = λν• λ is wavelength (in meters)• ν is frequency (in s-1)• c is speed (in m/s) • for light, c = 3.00 x108
• E = hν• h is Planck’s Constant (6.626 x10-34 J· s)
BOHR’S HYDROGEN ATOM
• Light is absorbed or emitted from electrons transitioning between energy levels.
• Since only certain energies are observed, only certain energy levels can exist.• This is called quantization of energy levels.• Think of a ladder instead of a ramp.
MATTER WAVES
• All matter has both particle and wave properties (wave/particle duality).
• Large objects moving slowly produce waves that are too small to observe.
• For small objects moving quickly (like electrons), wave properties are important.
𝜆=h𝑚𝑣
HEISENBERG UNCERTAINTY PRINCIPLE
• We can’t know both the exact location and energy of an electron.
• Since we do know the energy extremely well, we don’t know the location.
SCHRODINGER MODEL OF H
• Electrons act as standing waves• Only certain wave functions are “allowed”• Wave behavior is described by a wave function, Ψ.• Ψ2 describes the probability of finding the electron
in a certain location.• Also called the electron density
ORBITALS
• Each wave function describes the shape the electron cloud can take. These shapes are called orbitals.
• We organize orbitals by shells and subshells• Shells define size and energy (n = 1, 2, 3…)• Subshells define shape (s, p, d, f)
• Each subshell has a different number of orbitals• s = 1 orbital• p = 3 orbitals• d = 5 orbitals• f = 7 orbitals
ELECTRON SPIN
• Electrons exhibit a magnetic field• They don’t actually spin, but we think of them as
spinning.
• They can only spin two ways. • For sake of argument, we’ll call it up and down.
• Allowed spins: + ½ and – ½ .
SPIN AND MAGNETISM
• Paramagnetic: unpaired electrons will align in presence of a real magnet.
• Ferromagnetic (real magnets): unpaired electrons aligned in the same direction.
diamagnetic paramagnetic ferromagnetic
ELECTRON CONFIGURATIONS
• A listing of how many electrons occupy each orbital.
• 3 Rules• Aufbau Principle – Electrons fill lowest energy orbitals
first.• Pauli Exclusion Principle – Each orbital can hold two
electrons if they have opposing spins.• Hund’s Rule – Each subshell is filled in a way to give the
maximum number of unpaired electrons (maximum degeneracy).
THREE DIFFERENT NOTATIONS
• Electron Configuration• List subshells and how many
electrons they contain.• 1s22s22p63s1
• Noble Gas Notation• [Ne]3s1
• where [Ne] = 1s22s22p6.