chem chapter 7 Flashcards
degeneracy (long def)
in atoms, electrons occupy different energy levels/orbits. If multiple energy levels have the same energy, they are degenerate.
degenerate (short def)
In a single electron atom, subshells/orbits with the same quantum number are degenerate
what makes non-degeneracy?
sublevels with the same principal energy level
shielding
-electrons closer to the nucleus can shield electrons farther out from the nucleus causing them to to have a lower Zeff and have a higher energy
relate shielding to penetration
the closer, more penetrating orbital, shields the further out orbitals from the nucleus
penetration
orbitals with radial probability closer to the nucleus are more penetrated (they are closer to the nucleus)
paramagnetic
in the orbital diagram/chart- there are unpaired electrons (they are drawn to magnets)
diamagnetic
in electron chart/orbital diagram- paired electrons (slightly repel magnets)
what is the order of assigning electrons to orbitals?
1s, 2s, 2p, 3s, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p,
pauli exclusion principle
no two electrons can have the same quantum numbers (n,l,ml,ms)
-only two electrons in the same orbital and they must have opposite spins
aufbau principle
electrons fill lower energy orbitals first
hunds rule
when multiple degenerate orbitals are available, electrons fill each singly with parallel spins before pairing
-orbitals with the same n and l values are degenerate in a multi-electron atom
effective nuclear charge (Zeff)
-an atom with electrons closer to the nucleus will generally have a higher Zeff
-Zeff increases from left to right
-Zeff=atomic number - number of core electrons
valence electrons
electrons in the outermost shell (highest principal quantum number)
transition metal exceptions with filling behavior
groups 6B and 11B
-instead of having a full ns orbital and (n-1)d^4 or (n-1)d^9 they move one electron up to the (n-1)d orbital taken from the ns orbital
-Cr, Mo, Cu, Ag, Au
excited state electron configurations
the electron will be missing from a lower energy level subshell and moved to a higher energy sublevel
electron configurations of ions: cation
when an atom loses electrons (makes a cation), it loses the highest principle energy level first
electron configuration of ions: anions
electrons fill to minimize their energy and anions will continue the same filling pattern as other atoms
predicting ion charges: cation
look for which electrons will come off first: valence electrons
predicting ion charges: anion
look for how many electrons are needed to reach an octet (8e-)
ionization energy
-the amount of energy required to remove an electron from a neutral atom in the gas phase
-endothermic
ionization energy trend and exceptions on the periodic table
it increases left to right and up
-exceptions:
switch groups 2 and 13 (13 has lower IE than expected)
switch groups 15 and 16 (16 has lower IE than expected)
electron attachment enthalpy
the enthalpy change when a gaseous atom adds and electron forming a gaseous anion
this process is negative or exothermic
electron affinity
the energy required to detach an electron to form an anion with a -1 charge
typically positive and is endothermic
what is the periodic trend for electron attachment enthalpy and electron affinity?
it becomes more favorable (increases) from the left to the right and up the periodic table
what are the exceptions for EA and EAE
-row 2 has a lower (less favorable) than row three
-noble gases are very unfavorable
-group 2 and 15 are less favorable than expected so groups 1 and 2 switch and groups 14 and 15 switch
atomic radius
measure of the size of the atom
atomic radius periodic trend
atomic radius increases from the right to the left and down the periodic table (opposite of what you would think)
polarizability
tendency of an atom to become polarized
larger atoms have a higher polarizability because electrons are farther from the nucleus
polarizability on the periodic table
it increases from the left to the right and down the periodic table
IMPORTANT: cations are smaller and anions are larger!
electronegativity
measure of an atoms ability to attract electrons to itself
electronegativity on the periodic table
EN increases from the left to the right and up the table
HOWEVER, noble gases are excluded!
fluorine is the most electronegative and francium is the lest electronegative
