2: quantum mechanics model + trends

Question 1

constructive interference vs destructive interference

Answer 1

1st: 2 interacting waves are in phase (min and maxima aligned)
=> creating an amplitude that’s the sum of amplitudes of 2 waves

2nd: in opp. phase
min of 1 aligned with maxima of another
=> creating - amplitude
light cancel e/o

Question 2

what is the double slit experiment and what does it prove?

Answer 2

light passes through splits and defracts
=> creating light band (constructive interference) and dark band (destructive interference)

proving that light =/ particle only
bcs then it’d create 2 light particles

Question 3

standing vs travelling wave

Answer 3

standing: is bound and only oscilliate at certain frequency (v)
diff amplitude
have nodes

travelling: all point oscillate and travel in 1 direction
= amplitude

Question 4

more nodes => mroe energy bcs…

Answer 4

shorter wavelenght => higher frequency (v)

Question 5

find out all possible sets of wavefunctions f n = 3

Answer 5

n = 3
l = 0, 1, 2
ml = [3, 0, 0] [3, 1, [-1, 0, 1]] [3, 2, [-2, -1, 0, 1, 2]

Question 6

principal quantum #:
determines size & energy of orbital
nodes: _____

azimutal quantum #, l:
____ of orbital (which corresponds to _____ _____)
+ angular momentum of e-

_______________

magnetic quantum #, ml: _________

Answer 6

(n-1)

shape / spdf designation / ml = 0, n-1

-l to +l

Question 7

what is the spin quantum #?

Answer 7

distinguish 2 e- in each orbital
e- interact with the magnetic field
=> spin up (+1/2) or spin down (-1/2)
=> explain the 2 LINES from H emission spectrum

Question 8

where does the 1 node lie on 2p orbitals?

Answer 8

on y-z, z-x, and z plane

Question 9

Aufbau principle? Pauli’s Exclusion Principle? Hund’s rule?

Answer 9

Aufbau principle: e= occupy orbitals w/ lower in enrgy
Pauli: no e- may have the same set of quantum #
Hund’s Rule: arrange e- as unpaired as possible

Question 10

exception to isoelectronic species?

Answer 10

Copper and Chromium
bcs half-filled and fully filled are the most stable

Question 11

name all groups from group 1 -> 13 in their respective blocks

Answer 11

in s blocks: alkaline metal -> alkaline earth metal
in d block: transition metal
in p block: triels -> tetriels -> pnictogen -> chalcogen -> halogen -> noble gas
in f block: lathnoids (up) -> actinoids (below)

Question 12

trend of atomic radius and why?

Answer 12

increase (in bottom left corner)

increase down the group ‘ prbital size increase
increase from R -:> L ‘ attraction btw nucleus - valence gets weaker

Question 13

why is Mg2+ < Mg+ and O2- > O-?

Answer 13

bcs for = elements, dication < monocation and dianion > anion

Question 14

arrange these isoelectronic series: Ne, O2-, Na+, and F- from biggest to smallest and why?

Answer 14

O2- > F- > Ne > Na+ bcs…
most (+) species are the smallest
(-) is the argest

Question 15

ionization energy? e- affinity? electronegativity?

Answer 15

1st: eneryg to remove a valence from a gas phase atom

2nd: enrgy assoiciated w/ addition of e- to gas phase atom

3rd: ability of an atom to pull an e- towards it

Question 16

why is 1st ionization >first ionization energy?

Answer 16

bcs Z* increases
attraction btw nucleus-valence <
so needs more enrgy