Models of the Atom Red Book: Section 5.1 Blue Book:13.1
Rutherford’s FailureRutherford’s model could not describe behavior of atoms Think About It: Why do certain atoms react while others don’t? Why do some fireworks glow red and others green?
Bohr’s Atom Hypothesis: each electron exists in a certain “orbit” or “energy level” Electrons can never exist in between Higher energy levels are further from the nucleus
QuantaA quantum (pl. quanta) is the amount of energy required for an electron to move up an energy level
Quantum Mechanical ModelAlso called “electron cloud model”Mathematically-based
Quantum Mechanical Model Determines allowed electron energies and how likely it is to find an electron in various locations around the nucleus Dense cloud = high probability
Atomic Orbitals Region of space in which there is a high probability of finding an electronWhy It’s Important: The exact location of each electroncontrols the atom’s properties!
“Address” of ElectronEach electron will be found On a PRINCIPAL ENERGY LEVEL In one of several SUBLEVELS On an ORBITAL
Principal Quantum Numbers Each energy level is assigned a principal quantum energy number, n n can be 1, 2, 3, or 4, etc…
Sublevels Each principal energy level has specific sublevels where an electron can be found # of sublevels corresponds to principal quantum number Level 1 has 1 sublevel Level 2 has 2 sublevels…
SublevelsSublevels are given letter designationsspdf
The orbital names (s,Why s, p, p, d, f, g, h,...) ared, and f? derived from the characteristics of their spectroscopic lines: sharp, principal, diffuse and fundamental, the rest being named in alphabetical order. For mnemonic reasons, some call them spherical & peripheral.
1 Principal Energy Level st• 1 sublevel (s)• 2 electrons in s orbital• 2 total
2 Principal Energy Level nd• 2 sublevels (s and p)• 2 electrons in s orbital• 6 electrons in p orbitals• 8 total (10 combined with 1st)
3 Principal Energy Level rd• 3 sublevels (s, p and d)• 2 electrons in s orbital• 6 electrons in p orbitals• 10 electrons in d orbitals• 18 total (28 combined with 1st and 2nd)
4 Principal Energy Level th• 4 sublevels (s, p, d and f)• 2 electrons in s orbital• 6 electrons in p orbitals• 10 electrons in d orbitals• 14 electrons in f orbitals• 32 total (50 combined with 1st, 2nd, and 3rd)
Electron Arrangement Blue Book: 13.2 Red Book: 5.2
Electron ConfigurationWay that electrons are arranged in various orbitalsArrangement governed by three rules
Aufbau PrincipleElectrons first occupy orbitals of lowest energySublevels from some principal energy levels overlap others
Aufbau Diagrams Display the order in which orbitals are filled (to achieve the most stable configuration)