Electronic Structure Flashcards
Are there the same number of electrons in each shell? If not, how can # electrons be calculated for each shell?
2n^2 where n is shell number
Minimum number of electrons = 2
What is the name of the outermost shell containing electrons? Inner shells containing electrons?
Valence shell - outer
Core shell - inner
What is the effective nuclear charge? What does the effective nuclear charge account for? How is it calculated?
Effective nuclear charge is the attractive electrostatic force experienced by valence electrons to the nucleus. Accounts for attraction to positively charged nucleus, electrical repulsion from core shell, and minimal repulsion from surrounding valence electrons. Calculated by adding # protons + core shell electrons
Example: Li(7) vs Be(9)
Lithium has 3 protons + 2 negaitvely charged core shell electrons = +1
Berylium has 4 protons + 2 core shell electrons = +2
Effective nuclear charge increases from left to right
How are we able to learn about the pathways of electrons even though Hesienberg Uncertainty Principle principle states we cannot actually see an electron?
Moving electrons (current) produces magnetic fields. This is accounted for by two of the four quantum numbers (magnetic orientation and magnetic spin)
Do electrons with spin up or spin down fill orbitals first?
Spin up
What paramagnetism and diagmagnetism?
Paramagnetic atoms have unpaired electrons. Because electrons by nature have magnetic spin, without coupling them to their opposite spin, when a magnetic field is applied, a magnetic moment is created.
DIagmagentism is the opposite. They are not susceptible to magnetism
What is an orbital?
Region of space where an electron is most likely to be found. As distance from nucleus increases, probability of finding an electron drops exponentially
How many nodal planes do s,p and d orbitals have? Are the electrons found at the nucleus for each type?
s orbitals - 0 nodes
p orbital - 1 node
d orbital - 2 nodes
f orbital - 3 nodes
Only s electrons are found at the nucleus
What is Pauli Exclusion Principle?
No two electrons can have the same set of quantum numbers
What is Hund’s Rule? What is it implications for filling orbitals?
Electrons fill lower energy ORBITALS before starting to fill higher energy orbitals. This includes electrons filling degenerate orbitals before spin pairing because spin pairing is higher energy due to electron repulsion
What is Aufbau Principle?
Electrons fill lower energy SHELLS before starting to fill higher energy shells.
4s is lower in energy than 3d
Which electrons are always removed first during ionization?
Outer shell electrons (valence). Even though d orbital electrons are higher in energy, valence shell electrons are always removed first.
What are the exceptions to the Aufbau Principle?
Half or Completely Filled Subshells
Excited state electron configuration
Electron absorbs electromagnetic energy usually in the form of a photon. Moves to higher energy level (may be higher shell or higher orbital)
