atomic structure Flashcards
(IB) SPECTRA
use of a diffraction grating to break apart visible light
(IB) CONTINUOUS SPECTRUM
all the colours of the rainbow, no gaps
(IB) EMISSION SPECTRUM
black background, with bands of colour
(IB) ABSORPTION SPECTRUM
rainbow with gaps
(IB) order frequency, energy, and wavelength
wavelength
frequency
energy
(IB) STATIONARY STATES
part of bohr
certain allowable energy levels where the elctron is in a fixed circular orbit around the nucleus
(IB) how does the atom change to another stationary state
part of bohr
by ABSORBING or EMITTING a photon that matches the difference in energy between the 2 stationary states
(IB) how are emissions spectra produced
part of bohr
by atoms emitting photons when electrons in excited states return to lower energy levels
(IB) hydrogen emission spectrum
part of bohr
distances between levels converge
from 400-600 nm, purple, blue, green, red
(IB) transitions to n=2
seen in visible light region
(IB) transitions to n=1
higher in energy
UV region
(IB) transitions to n=3
lower in energy
IR region
(IB) why do elements have its own unique line spectrum
electronic signature is unique,
different # of electrons mean different magnitude of energy levels
(IB) pattern of each element with their line spectrum and electronic signature
of electrons inc. = # of spectral lines inc.
(IB) what has short wavelength
gamma rays
UV
(IB) what has long wavelengths
radio
microwave
IR
(IB) what region goes in 400 nm and 700 nm
UV = 400 nm
IR = 700 nm
(IB) ELECTROMAGNETIC SPECTRUM
alternating electric and magnetic waves travelling at the speed of light
(IB) constant for the speed of light
c = 3.00x10^3 mn^-1
(IB) WAVELENGTH
lambda
units are meters or SI prefix
(IB) FREQUENCY
of cycles of the wave (up down up) per sec
(f)
units= HERTZ
(IB) speed of light formula
c = f(wavelength)
(IB) Light as a particle
as matter gains energy, it emits EMR of varying wavelengths
(IB) MAX PLANCK
if matter emits certain quantities of energy, then an atom only has certain quantities of energy to give
(IB) planck’s formula and constant
E=hf
h= 6.63x10^-34
(IB) pros of bohr’s model
energy levels n=1 through infinity
convergence of energy levels
2n^2
(IB) cons of bohr’s model
orbits
treating electrons as particulate
(IB) QUANTUM THEORY
matter (electrons) has wavelike properties
(IB) DE BROGLIE
3D wave around nucleus, fits energy level
(IB) PAULI
orbital
2 electrons in a pair with opposing magnetic spins
magnetic attraction oppose electron-electron repulsions
(IB) ORBITAL
3D region of space surrounding the nucleus, with 90% of finding 1 or 2 electrons
(IB) HEISENBERG
uncertainty principle
(IB) UNCERTAINTY PRINCIPLE
can’t know the position and momentum of an electron at the same time
(IB) SCHRODINGER
wave equations whose solutions gave the probability densities of the location of an electron in an orbital
(IB) S orbital
2 electrons max
as sublevels inc.=size inc.
(IB) P orbital
3 orientations
2 lobes (equivalent in energy)
slightly higher in energy than s
(IB) D orbital
5 orientations
(IB) F orbital
7 orientations
(IB) energy sublevel order of orbitals
s<p<d<f
(IB) What causes energy levels and sublevels?
effect of nuclear charge
shielding effect (screening)
penetration
(IB) EFFECT OF NUCLEAR CHARGE
as # of protons in nucleus inc.=attraction of electrons to nucleus inc.
creates a stabilizing effect
(IB) Z ACTUAL
actual nuclear charge
(IB) SHIELDING EFFECT (SCREENING)
destabilizing
inner electrons repel outer
outer electron still has some attraction
Z effective < Z actual
creates successive E levels
(IB) PENETRATION
how close an electron can get to the nucleus
(IB) PENETRATION on the S orbital
shape allows for higher penetration
(IB) PENETRATION on the P orbital
high electron density away from nucleus
less penetration
higher energy
(IB) AUFBAU PRINCIPLE
add electrons to each sublevel of an atom in its ground state before electrons are added to the next sublevel
(IB) HUND’S RULE
spread out electrons into equal energy orbitals before doubling up
(IB) ANAMOLIES
Chromium: 6.5 filled orbitals that are ~same energy gives stability
Copper: 3d is filled out, 1 unpaired electron in 4s