PHYS 104 - Third Exam

• Pauli's Exclusion Principle

  No two electrons in an atom can exist in the same quantum state. Each electron must have a different set of quantum numbers n, l, ml, ms.
• Mass number


  In an Isotope notation, what is A?

  
• Atomic Number


  In an Isotope notation, what is Z?

  
• Symbol of the element


  In an Isotope notation, what is X?

  
• In an Isotope notation, what does the atomic number consist/s of?

  Atomic number of protons
• In an Isotope notation, what does the mass number A consist/s of?

  mass number: number of protons + number of neutrons
• What is the atomic number of an alpha particle a?

  2
• What is the mass number of an alpha particle a?

  4
• Degeneration where a particle can transform from a neutron to a proton, vice versa.

  Beta decay
• What is the atomic number of a beta particle e+?

  +1
• What is the mass number of a beta particle e+?

  0
• What is gamma decay?

  When a nucleus undergone an alpha decay or beta decay, the daughter nucleus might be in an excited state
• Highest EM wave

  Gamma wave
• Gamma decay

  When a particle undergoes beta and alpha decay, its daughter nuclei are in the excited state, when it de-excites, it undergoes gamma decay.
• In gamma decay, the atomic number Z, is 0 and the mass number A, is 0.
• Particles of odd half-integral spin are often referred to as

  Fermions
• Particles of 0 or integral spin are often referred to as

  Bosons
• The amount of energy it takes for an electron to pull away.

  Ionization Energy
• Two basic principles determine the structures of atoms with more than one electron:

  1 A system of particles is stable when its total energy is a minimum.

  2 Only one electron can exist in any particular quantum state in an atom.
• The most obvious is that in the symmetric case, both particles 1 and 2 can simultaneously exist in the same state, with a and b.
• In the antisymmetric case, two particles cannot be in the same quantum state.
• The fine-structure doubling of spectral lines arises from a magnetic interaction between the spin and orbital angular momenta of an atomic electron called spin-orbit coupling.
• J = L + S


  Total atomic angular momentum
• If there is no external magnetic field, the total angular momentum J is conserved in magnitude and direction.
• If there is an external magnetic field B present, then J precesses about the direction of B while L and S continue precessing about J. The precession of J about B is what gives rise to the anomalous Zeeman effect, since different orientations of J involve slightly different energies in the presence of B.
• If E(R) has a minimum, we will know that a bond can exist.
• The electron energy EA when R_0 is that of the 2p state of He. This energy is proportional to $Z^2/n^2$
• THE HYDROGEN MOLECULE - The spins of the electrons must be antiparallel
• THE H2+ MOLECULAR ION bonding requires a symmetric wave function.
• According to the exclusion principle, both electrons can share the same orbital provided their spins are antiparallel.
• COMPLEX MOLECULES - Their geometry depends on the wave functions of the outer electrons of their atoms
• Hybrid orbitals that consist of mixtures of s and p orbitals occur when the bonding energies they produce are greater than those which pure orbitals would produce.