Title: Chapter 5 Electrons in Atoms
1Chapter 5Electrons in Atoms
Different colors of light are associated with the
movement of electrons
25.1 Models of the Atom
- Key Concepts
- What was inadequate about Rutherfords atomic
model? - What was the new assumption in the Bohr model of
the atom? - What does the quantum mechanical model determine
about the electrons in an atom? - How do sublevels of principal energy levels
differ?
3- Rutherford (1897)
- Electrons move around a
- nucleus made of protons and neutrons
- Could not explain the _______________ properties
of elements - Ex why do metals change colors when
- heated?
chemical
4- Bohr (1913) proposed that
- electrons are found in specific
- paths, or _________, around a nucleus
- Each orbit has a __________ energy level
- Ex rungs of a ladder
- The higher an electron is on the
- ladder, the farther it is away from
- the nucleus
orbitals
fixed
5- Quantum ? the amount of energy needed to move an
electron from one energy level to another - Moving up energy levels ____________ energy
- Moving down energy levels _______ energy
(light) - Energy levels are not equally spaced
- It takes less energy to
- move between higher rungs
- or energy levels than lower
- ones
absorb
emit
6- Bohrs model only worked for hydrogen
- De Broglie (1923) proposed that small particles,
like electrons, have _____________ properties - Schrodinger (1926) devised a mathematical
calculation to describe the wave-like movement of
electrons - _________________________
- Determines the allowed energies an electron can
have and how _________ it is to find the electron
at various locations around the nucleus
wave-like
Quantum Mechanical Model
likely
7Movement of electron is similar to movement of a
propeller blade Blade may be anywhere in
the blurry region
Electron may be found anywhere within
the electron cloud
8- The energy levels in the quantum mechanical model
are labeled by _____________________________ (n) - n 1, 2, 3, 4, 5, 6
- Each principle energy level has sublevels that
correspond to different cloud shapes, called
_______________________
principle quantum numbers
Name Principle Quantum Number Symbol
n Represents energy levels Values any integer
1
atomic orbitals
9- 4 Different Atomic Orbitals
- S orbital _____________ (1)
- P orbitals __________________ (3)
- 3. D orbitals ____________________ (5)
- 4. F orbitals ___________________ (7)
spherical
dumbbells
four leaf clovers
Complex shapes
10Principle energy level Number of sublevels Type of sublevel
n 1 1 1s (1 orbital)
n 2 2 2s (1 orbital) 2p (3 orbital)
n 3 3 3s (1 orbital) 3p (3 orbitals) 3d (5 orbitals)
n 4 4 4s (1 orbital) 4p (3 orbitals) 4d (5 orbitals) 4f (7 orbitals)
Orbitals get bigger because they can hold
more electrons
11- Notice that n of sublevels and of different
shapes - The order of the shapes moves from lowest energy
to highest energy (s, p, d, f) - Example n 2 sublevel shapes s p
- Name the shape(s) be for the following
- n 1
- n 3
- n 4
s s, p, d s, p , d, f
12- Notice the number of orbitals per shape
- s 1 - d 5
- p 3 - f 7
- If n 3, then we will have 3 different shapes
(s, p d) - The s shape has 1 orbital available
- The p shape has 3 orbitals available
- And, the d shape has 5 orbitals available
- How many orbitals does the 3rd energy level have?
It has 9 orbitals
13- What is the relationship between n 3 and 9
available orbitals? - 9 32
- So, we can say that n2 of orbitals available
- We represent each orbital by listing the energy
level followed by the orbital shape - 1s
- n 1, orbital shape sphere
- 3d
- n 3, orbital shape clover
14- How many orbitals are in the 3s sublevel?
- Well, we know that n 3 and that the orbital
shape s - The 3rd energy level can have 9 total orbitals
between s, p, dbut we are only looking the s
orbital - ? There is only 1 orbital in the 3s sublevel
- Each orbital available can hold 2 electrons
- s 1 orbital 2 electrons
- p 3 orbitals 6 electrons
- d 5 orbitals 10 electrons
- f 7 orbitals 14 electrons
15- So, when n 4, we can have
- s 1 orbital 2 electrons
- p 3 orbitals 6 electrons
- d 5 orbitals 10 electrons
- f 7 orbitals 14 electrons
- 32 total electrons 2n2
16- of electrons at each main level 2n2
- n 1 _____ electrons
- n 2 _____ electrons
- n 3 _____ electrons
- n 4 _____ electrons
2
8
18
32
17Key Answer 1
- What was inadequate about Rutherfords atomic
model?
It did not explain the chemical properties of
elements
18Key Answer 2
- What was the new assumption in the Bohr model of
the atom?
An electron is found only in specific orbits
19Key Answer 3
- What does the quantum mechanical model determine
about the electrons in an atom?
The likelihood or probability of finding
electrons in various locations around the nucleus
20Key Answer 4
- How do sublevels of principal energy levels
differ?
The sublevels are the different shapes of the
electron clouds
215.2 Electron Arrangement in Atoms
- Key Concepts
- What are the three rules for writing the electron
configurations of the elements? - Why do actual electron configurations for some
elements differ from those assigned using the
aufbau principle?
22- Unstable arrangements become more stable by
____________ energy - Does the rock formation in the picture look
stable? _______ - What will it eventually do to become more stable?
losing
No
It will fall or rearrange
23- In an atom, _________ and the ___________
interact to make the most stable arrangement
possible - The ways in which electrons are arranged around
the nuclei of atoms are called __________
____________________
electrons
nucleus
electron
configurations
24- Three rules tell you how to find the electron
- configurations of atoms
- 1. ______________________
- 2. ______________________
- 3. ______________________
Aufbau Principle
Pauli Exclusion Principle
Hunds Rule
25- Aufbau Principle electrons occupy the orbitals
of __________ energy first
lowest
Each box represents an orbital
Will electrons occupy the 2s orbital or the 2p
orbital first? __________
2s
26- What do the three boxes by 2p represent?
- Which is higher, 3d or 4s?
-
The three dumbbell orbitals px, py, pz
3d
27- Pauli Exclusion Principle an atomic orbital may
________ at most two electrons that have
____________ spins
hold
opposite
Counterclockwise
Clockwise
________________________
___________________
28- Hunds Rule electrons occupy orbitals of the
same energy in a way that makes the number of
electrons with the ______ spin direction as large
as possible - Orbitals in the same sublevel have ________
energy levels - They all must have electrons with the same spin
first - Practice Put three electrons into the 2p
sublevel
same
equal
2p
x
y
z
29- Practice put four electrons into the 2p
sublevel - Put five electrons into the 2p sublevel
2p
x
y
z
2p
x
z
y
30- If an orbital only has one electron in its box,
it is called ______________ - Ex How many unpaired electrons are in the
following sublevel?
unpaired
4
3d
xy
xz
yz
x2-y2
z2
31- We use all three rules to write a shorthand
method for showing the electron configurations of
an atom - It consists of
- The _____________ of the main energy levels
- The ____________ of the atomic orbital
- _____________ indicating the of electrons
Number (n)
letter
Superscript
32- Practice Hydrogen
- How many electrons does hydrogen have? ___
1
1s1
_______________
33- Practice Helium
- How many electrons does helium have? ____
2
1s2
_______________
34- Practice Lithium
- How many electrons does lithium have? ____
3
1s22s1
35- Practice Carbon
- How many electrons does carbon have? ____
6
1s22s22p2
36- Practice Sulfur
- How many electrons does sulfur have? ____
16
1s22s22p63s23p4
37- Practice Titanium
- How many electrons does titanium have? ____
22
1s22s22p63s23p64s23d2
38 39H He
Li Be B C N O F Ne
Na Mg Al Si P S Cl Ar
K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr
Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe
Cs Ba 57-71 Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn
Fr Ra 89-103 Rf Db Sg Bh Hs Mt Ds Uuu Uub Uuq
--- s block
40H He
Li Be B C N O F Ne
Na Mg Al Si P S Cl Ar
K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr
Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe
Cs Ba 57-71 Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn
Fr Ra 89-103 Rf Db Sg Bh Hs Mt Ds Uuu Uub Uuq
--- s block --- p block
41H He
Li Be B C N O F Ne
Na Mg Al Si P S Cl Ar
K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr
Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe
Cs Ba 57-71 Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn
Fr Ra 89-103 Rf Db Sg Bh Hs Mt Ds Uuu Uub Uuq
--- s block --- p block --- d block
42- Exceptional Electron Configurations
- Some atoms do not follow the aufbau principle
- Ex Copper 29 electrons _________________
- Actually is
__________________ - Ex Chromium 24 electrons_______________
- Actually is ________________
1s22s22p63s23p64s23d9
1s22s22p63s23p64s13d10
1s22s22p63s23p64s23d4
1s22s22p63s23p64s13d5
43- These atoms are trying to become more
______________ by having sublevels that are least
______ full. - Filled and half-filled energy sublevels are more
stable than partially-filled energy sublevels.
stable
half
44Key Answer 1
- What are the three rules for writing the electron
configuration of elements?
Aufbau Principle Pauli Exclusion Principle Hunds
Rule
45Key Answer 2
- Why do the actual electron configurations for
some elements differ from those assigned using
the aufbau principle?
They are trying to become more stable
46- What is the basis for exceptions to the aufbau
diagram? - Filled and half-filled orbitals are more stable
than partially filled orbitals
475.3 Physics and the Quantum Mechanical Model
- Key Concepts
- How does quantum mechanics differ from classical
mechanics? - How are the wavelengths and frequency of light
related? - What causes atomic emission spectra?
48- The quantum mechanical model grew out of the
study of ___________, which also moves in
___________ - If all objects have a wavelike motion, why cant
we see this for ordinary objects like baseballs
or trains? - Classical Mechanics describes the motion of
__________ objects - Quantum Mechanics describes the motion of
________________ particles and __________
light
waves
Mass has to be very small in order to detect
wavelength
large
subatomic
atoms
49- Complete Wave Cycle
- Starts at _________
- Moves to its ___________ point and __________
point - Returns to ___________
zero
highest
lowest
zero
50- Amplitude
- a waves _________ from ______ to the __________
- Wavelength (?)
- Distances between the _____________
zero
height
crest
crests
51- Frequency (v)
- Number of wave cycles to pass a certain point per
unit of _________ - Unit ______________________
- (SI) ____________ or ______
time
Cycles per second
Hertz (Hz)
S-1 (1/s)
52- The product of wavelength (?) and frequency (v)
always equals a constant (c), the
____________________ - c 2.998 x 108 m/s
-
Speed of light
? x v c
53- Wavelength (?) and frequency are ____________
proportional - What happens to frequency when wavelength
decreases?
inversely
Frequency increases
54- Sample Problem 5.1
- Calculate the wavelength (?) of the yellow light
emitted by the sodium lamp shown above if the
frequency of the radiation is 5.10 x 1014 Hz. - c ?v
- c ?
- v
- 2.998 x 108 m/s
- 5.10 x 1014/s
5.88 x 10-7 m
55- According to the wave model, light consists of
___________________ waves - Electromagnetic radiation includes
- _____________________
- _____________________
- _____________________
- _____________________
- _____________________
- _____________________
- _____________________
- ______________________
electromagnetic
Radio waves
Radar
Microwaves
Infared
Visible light
Ultraviolet light
X - Rays
G amma rays
56- Which type of electromagnetic radiation has the
lowest frequency?
Radio waves
57- The different frequencies of visible light can be
seen when sunlight is passed through a ________
prism
ROYGBIV
58- What color in the visible spectrum has the
highest wavelength?
Red
59- Atoms emit light when their electrons move from a
__________ energy level to a _________ energy
level - Higher energy levels ________ state
- n 2, 3, 4, 5,
- Lowest energy level _________ state
- n 1
higher
lower
excited
ground
60- The frequencies of light emitted by each element
that separate into distinct lines is called its
____________________________ - Unique to each element like a ______________
Atomic emission spectra
fingerprint
Each gas glows a different color
61Key Answer 1
- How are wavelength and frequency of light related?
They are inversely proportional
62Key Answer 2
- What causes atomic emission spectra?
Electrons of atoms moving from an excited state
to a lower state
63Key Answer 3
- How does quantum mechanics differ from classical
mechanics?
Quantum mechanics small objects Classical
mechanics large objects