SI worksheet 2
CH115 Dr. Hamilton
1. What is the photoelectric effect?
When a light with a high enough frequency or low enough wavelength (blue light, NOT red) hits a metal, electrons are
emitted from the metal. One photon hitting the metal equals one electron emitting from it. Blue light has a higher
energy/lower wavelength/higher frequency so it can emit electrons off a metal unlike red light which is low in energy/high
in wavelength/low in frequency.
2. What is the Schrodinger equation? Label each part of the equation.
E for energy, H hat for Hamiltonian operator. And Psi for wave function. NOT NEEDED ON TEST.
3. In the Copenhagen interpretation, the absolute value of the wave function squared was said to be what? And the
wave function itself was said to be what?
The probability of density. The probability of amplitude. NOT NEEDED ON TEST.
4. Applied to the hydrogen atom, the wave function represented what?
The probability of finding an electron around the nucleus.
5. Look at the diagram below.
n= 6
n=5
n=4
n=3
n=2
n=1
a) Which arrow from the left represents the largest gain in Energy of the atom? What would be the sign
for this energy (+/-)? Arrow 1. + Because the input of energy into the atom causes the electrons to
get excited and jump energy levels. The largest jump is from 1 to 2, then the increments decrease
dramatically.
b) Which arrow from the left represents the largest loss in Energy of the atom? What would be the sign
for this energy (+/-)? Arrow 6 – because the excited electron desires to fall back to its original state,
or the ground state. Since the electron falls down energy levels, a photon is emitted in the process as
energy. This means the atom itself lost energy so the charge for energy will be negative.
c) Which arrow from the left represents the largest gain of Energy for an emitted photon? What would
be the sign for this energy (+/-)? Arrow 6 + because we are now talking about the photon which was
emitted in the process and NOT the atom itself. Since the photon was emitted as a form of energy, it
is positive.
d) Arrow 2, or the electron, jumps from n=2 to n=6 while arrow 4 jumps from n=1 to n=3. Which
arrow gained the most energy? Arrow 4 gained the most energy because the jump from n=1 to n=2 is
MUCH larger than the any of the jumps after n=2.
e) Which arrow, 6 or 7, lost the most energy? Arrow 6 because the fall from n=2 to n=1 is much larger
than any fall from energy levels higher than n=2.
f) Did arrow 4 gain more energy than arrow 6 lost? No, the exact same energy was gained that was
lost. The jump and fall distance is the exact same. Therefore, the gain and loss of energy is the exact
same.
6. What is the energy of a PHOTON emitted when an excited electron in the atom drops from n=5 to n=3?
N=5: 2.179e-18/5^2= 8.716e-20
N=3: 2.179e-18/3^2= 2.42e-19
drops in energy levels.
2.42e-19 – 8.716e-20= 1.55e-19 J
a positive energy is answered because a photon is emitted when an electron
7. Pertaining to quantum numbers, if n=3, what are all the possible values for l, ml, and ms?
l=0, 1, 2
l can be 0 to (n-1)
ml= -2,-1,0,1,2
ms=-1/2, +1/2
8. What is the electron configuration of Carbon?
1s2 2s2 2p2
9. What is the electron configuration of Silicon?
1s2 2s2 2p6 3s2 3p2
10. What is the noble gas configuration of Potassium?
[Ar]4s1
11. Which subshell is larger? 1s or 2s? 3p or 4p?
2s. 4p. the larger subshell number is always larger.
12. What quantum number pertains to subshells? Label which number is associated with each subshell (s, p,
d, f).
Angular quantum number or l. s= 0, p=1, d=2, f=3.
13. Draw the shape of each subshell.
14. What would be the quantum numbers n and l for the element Sulfur? Barium? Hydrogen?
Sulfur- n= 2, l= 1
found on period 2 and in the p subshell
Barium- n= 6, l= 0
found on period 6 and in the s subshell
Hydrogen- n=1, l=0
found on period 1 and in the s subshell
15. How many orbitals does the subshell s have? What about p, d, and f? What is the maximum number of
electrons an orbital can have?
1. 3. 5. 7. Maximum number is 2. i.e. when l(subshell)= p (l=1) then ml = -1, 0, 1. That is 3 whole orbitals.
16. How many orbitals exist at l=0? l=1? l=2? What about n= 2? n= 3?
1. 3. 5. 4. 9.