LECTURE 3 โ Chapters 5
Slide NumberNotes ๎
11 EX.
-binding energy = 7.21 x 10^-19 J
-E of photon > or = 7.21 x 10^-19 J
-Longest wavelength = 6.63x10^-34 Js (3.00x10^8 m/s) / 7.21 x
10 ^-19 J = 2.76 x 10^-7 m = 276 nm
-Will light with 290 nm eject electrons? NO
-This is because increasing wavelength = decreasing frequency
-276nm is the longest wavelength that will eject electrons
-below this threshold, no electrons ejected
-increasing wavelength is decreasing energy
-energy of photon = binding energy + kinetic energy of electron
= 7.21x10^-19 J + 2.5 x 10^-19J = 9.7x10^-19J
-v = E/h = 9.7x10^-19 J / 6.676x10^-34Js = 1.5x10^15/s
-wavelength = c/v = 3.00x10^8 m/s / 1.5 x 10^15/s = =210nm
13 -monochromatic = one colour
-energy needed to eject energy from Zn > than for Na therefore
A wrong
-same number of electrons ejected from both metals because
same intensity of light shone for both therefore B and C wrong
-zinc has a higher threshold frequency, therefore there is less
kinetic energy therefore D is wrong
-Ans: E
14 -electron can only be at certain levels of the atom
-like stairs: a fixed number of positions
-unlike a ramp: an electron cannot be anywhere, cannot fall from
just any position
16 -de Broglie suggested that electrons may behave as waves
-important for small objects (ie. electrons) because of the inverse
relationship such that the smaller the mass, the longer the
wavelength
17 -uncertainty significant for tiny masses
-electronic structure BEFORE 1900: light as waves, continuous,
spread out, mass-less; matter as discrete particles with mass and
position
-experiments (ie. blackbody radiation, photoelectric effect),
however, put forward the wave-particle duality (waves behaving
as particles and particles behaving as waves)
-instead of trying to pinpoint the exact location of electron, focus
instead on probability of finding the electron
18 - the many solutions refer to the different locations of the electron
19 - Schrodingerโs equation gives orbitals and energy
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