Chapters 6 & 7 Flashcards
electronic structure (of atoms)
arrangement and energy of electrons
Electromagnetic radiation (radiant energy)
carries energy through space
- moves at speed of light (c)
C =
c = λv
c = 3.00 x 10^8 m/s
wavelength (λ)
distance b/w 2 wave peaks
- meters (or nm)
Frequency(v)
of complete cycles (wavelengths) that pass a given point/second
- v = 1 s^-1
Electromagnetic Spectrum
electromagnetic radiation arranged in increasing wavelength
blackbody radiation
emission of light from hot objects
photoelectric effect
emission of electrons from metal surfaces which light in shone
emission spectra
emission of light from electronically excited gas atoms
Quantum physics
physics to describe atoms
Quantum theory
to describe electronic structure of atoms
Photoelectric effect
every metal has diff energy level which ejects e-
Planck’s constant: E=
E = hv
- to calculate the energy required to remove an electron
Emission spectra
observed energy emitted when electric current is passed thru
- radiation–>component wavelengths
Continuous spectrum
(the “rainbow”) from white light source
Line spectrum
radiation of only specific wavelengths; discrete wavelengths observed
- each element = unique line spectrum
Rydberg formula
1/λ = (RH)x((1/n1^2) - (1/n2^2))
- RH = 1.096 x 10^7 m^-1
Bohr equation
∆E = Ef-Ei
- ∆E = (-2.18 x 10^-18 J)(1/n^2-1/n^2)
ground state
lowest energy state of atom
- n=1
excited state
higher energy state of atom
- n=2+
λ =
h / mv
Heisenberg Uncertainty Principle
can’t know both momentum and position of a particle
Wave functions
describes the electron (orbital) and its energy
electron density
probability e- can be found in specific location
orbitals
hold 2 electrons
electron shell (n)
orbitals w/ same n value
- ex: all orbitals w/ n=3 = third orbital
subshell
diff orbital types w/in shell
s orbital
L = 0
- spherical
p orbital
L = 2
- 2 lobes w/ 1 node
f orbital
L = 3
degenerate orbitals
orbitals at same energy level; n =
electron spin
describes magnetic field; (+/-) 1/2
pauli exclusion principle
each electron in atom must have distinct quantum numbers; need image to describe
electron configurations
way electrons are distributed in an atom
- orbitals filled in order of increasing energy
- n = energy level
- letter = type of orbital
- superscript = number of electrons in orbitals
ground state
most stable organization at lowest possible energy
orbital diagram
each orbital denoted by box and electron by half arrow
Hund’s rule
“sharing is caring”
- there must be 1 e- (w/ same spin) per orbital before pairing with 2nd opposite spin
Valence electrons
same group (↓) have same # of e- in outer shell; part after [ ]
core electrons
filled inner-shell electrons; part in [ ]
transition elements
10 elements touching step-line
- d-block
Lanthanide elements
4f
Actinide elements
5f
Periodicity
repetitive pattern of property for elements based on atomic number
effective nuclear charge (Zeff)
Zeff = Z – S
feel pull of nucleus more:
- changes w/ # of protons
- increase Zeff = increase nucleus size = incr. pull
- decrease Zeff = decr. nucleus size = decr. pull
Slater’s Rules
ignore all outer e- beyond one of interest
Nonbonding radius (van der Waals radius)
½ shortest distance separating 2 nuclei during collision of atoms
Bonding atomic radius (covalent radius)
½ distance b/w nuclei in a bond
- Can’t get any closer bc of core e- repulsion
- Bonding radius < nonbonding radius
cations
- smaller than parent atoms
- e- removed
- repulsions b/w e- = reduced
anions
- larger than parent atoms
- e- added
- repulsions b/w e- = increased
isoelectronic series
ions have the same # e-, diff # of protons
- calculate number of ions and compare
Ionization energy
energy required to remove 1 e- from ground state of a gaseous atom or ion
- larger ionization energy # = more difficult to remove e-
first ionization energy
- removing e- from gaseous element
ex: Al (g) –> e- + Al+ (g)
Electron affinity
measures attraction/affinity of atom for added electron
Ionization energy measures energy change when atom __ e-
loses
Electron affinity measures energy change when atom __ e-
gains
increasing atomic radius
Increasing:
- right to left
- top to bottom
(same as increasing metallic character)
increasing ionization energy
Increasing:
- left to right
- bottom to top
(same as increasing electron affinity)
increasing electron affinity
Increasing:
- left to right
- bottom to top
(same as increasing ionization energy)
increasing metallic character
Increasing:
- right to left
- top to bottom
(same as increasing atomic radius)
