Transcript 4-3 Another Look at the Atom

4-3 Another Look at the Atom
Line Spectra
 A spectrum
that contains only certain colors, or
wavelengths, is called a line spectra.
 All elements emit light when vaporized, or
electricity passed through.
 Atoms absorb energy, then give it off in the form
of light.
 Each
element has a unique line spectra.
 Also referred to as emission spectra
Sample Emissions
The Bohr Model of Hydrogen Atom
 Why
do elements emit different wavelengths of
radiation?
 Bohr
realized that the wavelengths had to do with
quantized energy proposed by Planck.
 Electrons in the atom are quantized
 Each orbital has different energies.
 When energy is absorbed electrons jump up in energy
levels, when released energy is given off as light
 Each
energy level was labeled by the quantum
number , n


n =1 was the lowest energy state
n= 2 a more excited state…..and so on.
 Using
Planck’s equation E = hv
 Calculated
frequency
 Matched for Hydrogen only
Bohr’s Model

His model was only able
to accurately predict for
Hydrogen with one
electron.
Matter Waves
 Planck
and Einstein described light as consisting of
photons – or quanta of energy.
 Light
travels as a wave
 Light interacts with matter as a particle
 Does
matter have a duel nature as well?
 De
Broglie referred to this as matter waves

Later scientists noticed
patterns in electrons that
had been reflected from
metals after being
bombarded.
Heisenberg Uncertainty Principle
 The
position and momentum of a moving object
can not simultaneously be measured and known
exactly.
 Due
to the duel nature of matter and energy
 Only important with small scale objects
 For
example, This means that we cannot know for
sure where an electron is at any given time within
an atom.

We can only know the probability of finding an electron,
not its exact location.
 Orbital – a 3-dimensional region around the nucleus
that indicates the probable location of an electron.