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waves amplitude
wavelengthfrequency
light
energy level
cres
t
origin
ROYGBIV
electrons
EMS
energy
Photoelectric effect
Electron.1
Wave nature of light› Electromagnetic (EM) radiation- E emits wave
like behavior › All waves have:
Wavelength- () distance from crest to crest Frequency- () # waves past a given point per
second (s-1) Amplitude- height of wave from crest to origin
› All light travels at speed of light, c = 3.00 x 108 m/s c=
Electron -1
EM spectrum› Radio Microwave Infrared Visible UV X-
ray Gamma Low E High E
High Low Low High
› Visible Light: Continuous spectrum ROYGBIV Low E High E
High Low Low High
ROYGBIV
Violet: 400- 420 nm Blue: 420- 490 nm Green: 490- 580 nm Yellow: 580- 590 nm Orange: 590- 650 nm Red: 650-700 nm
Electron -1
What is the frequency of green light, which has a wavelength of 4.90 x 10-7 m?
An X-ray has a wavelength of 1.15 x 10-10 m. What is its frequency?
A popular radio station broadcasts with a frequency of
9.47 x 107 s-1. What is the wavelength of the broadcast?
Hz = waves/sc= 3.00 x 108 m/s
Electron -1
Particle Nature of light › Quantum- minimum amount of E gained or
lost by an atom › Quantitized E- E gained in packet (NOT
continuous) E=hn
E= energy in Jh= Planck’s Constant 6.6262 x 10-34Js= frequency (s-1)
Electron -1
What is the energy of each of the following types of radiation?› 6.32 x 1020 s-1
› 9.50 x 1013 Hz› 1.05 x 1016 s-1
What types of radiation are the above?
Electron -1
Photoelectric effect- › Photoelectrons are emitted from a metals
surface when light of certain frequency shines on it Ex. solar calculators, automatic doors
› Each metal has its threshold for the photoelectric effect
› If light is shined on metal that doesn’t have the correct frequency, no matter how long, e- will not be emitted
Lab Conclusion Due tomorrow! Must be typed. Explain what you did in the lab. Explain what happened. Explain the science behind what
happened (photoelectric effect). How you calculated wavelength,
frequency, and energy & identified the unknown salts.
Reflection…what you liked, what you didn’t like (if any).
Electron -1
Atomic Emission Spectra › e- excited will jump to another E level,› As they fall they emit E (light) › n of the waves allow for a unique color
(NOT a continuous color spectrum like a white light)
› Atomic Emission
Electron -2 Bohr- e- only have “allowable E states”
› Normally in ground state› e- around nucleus in orbits› Lower the E, closer the orbit to the nucleus› Quantum number (n)- lowest E state
Schrodinger-quantum mechanical model of atom using wave properties of e- predicts e- will be found in orbitals, increase D of cloud = higher probability of e-
Electron -2 Principle quantum number (n)- tell
relative sizes & shapes of orbitals Higher n = bigger orbital = increased
time of e- away from nucleus Levels contain same number of
sublevels as level numberLevel Sublevels Sublevel
Called
1 1 s
2 2 s, p
3 3 s, p, d
4 4 s, p, d, f
Electron -2
** Each orbital can only hold 2 e-
Sublevel # Orbitals # e- held
s 1 2
p 3 6
d 5 10
f 7 14
Electron -3
Aufbau principle- each e- occupies lowest E orbital available
Electron Configuration- arrangement of e- in orbitals around atom› Lower E more stable than high E› Lowest E= ground state
Example:
1s2 1 is n s is sublevel 2 is number of e- in sublevel & is a superscript
› All orbitals in each E sublevel are equal (the three orbitals are =E) Fill s, p, d, f, for each level Orbitals can overlap
Electron Sequence Model
1s
2s
3s
4s
5s
6s
7p
6p
5p
4p
3p
2p
6d
5d
4d
3d
4f
5f
7s
Follow the yellow brick road
Electron Sequence by the Periodic Table
1s
La
Ac
1s
5f
4f
2s
3s
4s
5s
6s
7s
2p
3p
4p
5p
6p
3d
4d
5d
6d
The Periodic Table1
H3
Li11
Na19
K37
Rb55
Cs87
Fr
4
Be12
Mg20
Ca38
Sr56
Ba88
Ra
21
Sc39
Y57
La89
Ac
22
Ti40
Zr72
Hf104
Rf
23
V41
Nb73
Ta105
Db
42
Mo74
W106
Sg
25
Mn43
Tc75
Re107
Bh
26
Fe44
Ru76
Os108
Hs
27
Co45
Rh77
Ir109
Mt
28
Ni46
Pd78
Pt110
Uun111
Uuu
30
Zn48
Cd80
Hg
8
O16
S34
Se52
Te84
Po
7
N15
P33
As51
Sb83
Bi
6
C14
Si32
Ge50
Sn82
Pb
5
B13
Al31
Ga49
In81
Tl
9
F17
Cl35
Br53
I85
At
2
He10
Ne18
Ar36
Kr54
Xe86
Rn
90
Th91
Pa92
U93
Np94
Pu95
Am96
Cm97
Bk98
Cf99
Es100
Fm101
Md102
No103
Lr
58
Ce59
Pr60
Nd61
Pm62
Sm63
Eu64
Gd65
Tb66
Dy67
Ho68
Er69
Tm70
Yb71
Lu
24
Cr29
Cu47
Ag79
Au112
Uub114
Uuq116
Uuh118
Uuo
s
d
p
f
s1 s2 d1 d2 d3 d4 d5 d6 d7 d8 d9 d10 p1 p2 p3 p4 p5 p6
f1 f2 f3 f4 f5 f6 f7 f8 f9 f10 f11 f12 f13 f14
1
2
3
4
5
6
7
4
5
Electron -3
Electron Orbital Diagram: visually shows e- placement around the nucleus› Each orbital gets own box
Orbital # Orbitals # electrons held # boxes
s 1 2 1
p 3 6 3
d 5 10 5
f 7 14 7
Electron -3
Pauli Exclusion Principle- only 2 e- can occupy an orbital. Each w/ opposite spins show w/ arrow up and down
NOT Hund’s Rule- e- w/ same spin must occupy
each E level in a sublevel before doubling up› Example: when filling the p sublevel with 4e-, each
box gets 1 before doubling up one box
NOT
Electron Configurations
F – 1s22s22p5
Cl – 1s22s22p63s23p5
Al – 1s22s22p63s23p1
Br - 1s22s22p63s23p64s23d104p5
1s 2s 2p 3s 3p 4s 3d 4p
1s 2s 2p 3s 3p 4s 3d 4p
1s 2s 2p 3s 3p 4s 3d 4p
1s 2s 2p 3s 3p 4s 3d 4p
Electron Configurations Sc
K
P
B
1s 2s 2p 3s 3p 4s 3d 4p
1s 2s 2p 3s 3p 4s 3d 4p
1s 2s 2p 3s 3p 4s 3d 4p
1s 2s 2p 3s 3p 4s 3d 4p
Electron -3
Other helpful hints- › #e= # p = atomic number if neutral atom› Add superscripts to get the #e, #p
Electron -3 Noble Gas Configuration
› Go back to the last noble gas› Write symbol for noble gas in brackets› Write rest of configuration
Na Complete Configuration: 1s22s22p63s1
Na Noble gas Configuration: [Ne] 3s1
Exceptions to electron configuration:› e- want to be stable› Stable is a full or ½ full e- shell› Cr- [Ar] 4s23d4 [Ar] 4s13d5
› Cu- [Ar] 4s23d9 [Ar] 4s13d10
Electron -3
Valence electrons- e- in outer most level› Put in noble gas configuration› Count e- in highest level
Ex: Na 1s22s22p63s1 has 1 valence e-
Cs [Xe] 6s1 has 1 valence e-
Cu [Ar] 4s13d10 has 1 valence e-
S [Ne] 3s23p4 has 6 valence e-
Lewis Dot Structures- shows valence e- around symbol
Li N Be O
B F C Ne
Properties of the d and f-Block Elements
Magnetism – ability to be affected by magnet
Diamagnetism – all e- are paired, substance is unaffected or slightly repelled by magnetic field
Paramagnetic – unpaired electron in the valence orbital is attracted to magnetic field
Ferromagnetism – strong attraction of substance, ions can align in direction of field and form permanent magnet