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Sections 11.3 and 11.4 –
Emission of Energy by Atoms and
Atomic Emission Spectra
- Learning objective:
- Rank the energy of electronic
transitions using an atomic emission
spectrum.
- Main ideas:
- Atoms must release energy that they
have absorbed; a lot of that energy is
released as visible light.
- Energy is released from atoms at
specific values (quantized), not at
any possible value (continuous).
- Red light is the lowest energy visible
light, and violet light is the highest
energy visible light.
Sections 11.7 and 11.8 – Orbital Energy and
Shape
• Learning objectives:
• Classify orbitals by energy and shape.
• Identify valid sets of quantum numbers based on the rules.
• Match sets of quantum numbers to an orbital.
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Sections 11.7 and 11.8 – Orbital Energy and
Shape
• The area in which an electron is likely to exist
is called an orbital, which is represented by a
set of quantum numbers.
• Quantum numbers provide all information
needed to describe an electron.
• There are specific rules to use when writing
sets of quantum numbers.
• Orbital shapes are predicted by mathematical
models, and each type of orbital has a
different shape, which can be match to a set
of quantum numbers.
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A. S. Stodolna, A. Rouzée, F. Lépine, S. Cohen, F. Robicheaux, A. Gijsbertsen, J. H. Jungmann, C. Bordas, and M. J. J. Vrakking Phys. Rev. Lett. 110 , 213001 – Published 20 May 2013
Quantum number Description Allowed Values
n Energy level and distance from nucleus Any integer > 1
l Shape^ Any integer from 0 to n-
l = 0, s orbital l = 1, p orbital l = 2, d orbital
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The quantum number ‘l’ provides information on the shape of the orbital.
As ‘l’ increases, energy increases (becomes more positive), and the orbital
has a different shape with more separate lobes.
Copyright @ 2017 Pearson Canada, Inc.
Quantum number Description Allowed Values
n Energy level and distance from nucleus Any integer > 1
l Shape^ Any integer from 0 to n-
ml Number of each orbital shape^ Integers from –l to +l
The quantum number ‘ml ’ provides
information on the number and
orientation of orbitals with each shape.
As the number of ‘ml ’ values increase,
the number of orbitals increase:
- If l=0, then m (^) l =0. There is one m (^) l value, so
there is one s orbital.
- If l=1, then m (^) l = -1, 0, or 1. There are three
m (^) l values, so there are three p orbitals.
- If l=2, the m (^) l = -2, -1, 0, 1, 2. There are five
m (^) l values, so there are five d orbitals.
Quantum number Description Allowed Values
n Energy level and distance from nucleus Any integer > 1
l Shape^ Any integer from 0 to n-
ml Number of each orbital shape^ Integers from –l to +l
ms Electron “spin”^ + or – ½
The quantum number ‘ms’ is the spin quantum number. It points to a
specific electron in a subshell and has values of either + or -1/2.
Quantum number Description Allowed Values
n Energy level and distance from nucleus Any integer > 1
l Shape^ Any integer from 0 to n-
ml Number of each orbital shape^ Integers from –l to +l
ms Electron “spin”^ + or – ½
These are the rules which govern the quantum number for the electron.
Memorize this!
Quantum number Description Allowed Values
n Energy level and distance from nucleus Any integer > 1
l Shape^ Any integer from 0 to n-
ml Number of each orbital shape^ Integers from –l to +l
ms Electron “spin”^ + or – ½
We can use the notation, (n, l,ml , ms ), to organize the quantum
numbers that describe an electron in our system.
Use this notation to write the quantum numbers for an
electron where: n = 2, l = 0, ml = 0, ms = -1/2. What kind of
orbital is this?
Answer: (2, 0, 0, -1/2), S-orbital
Quantum Numbers I (SquareCap #2-4)
Solution
First determine the possible values of l (from the given value of n ). Then determine the possible values of m (^) l for each possible value of l. For a given value of n , the possible values of l are 0, 1, 2,..., ( n – 1).
n = 4; therefore l = 0, 1, 2, and 3
For a given value of l , the possible values of ml are the integer values including zero ranging from – l to + l. The name of an orbital is its principal quantum number ( n ) followed by the letter corresponding to the value l. The total number of orbitals is given by n^2.
What are the quantum numbers and names (for example, 2 s , 2 p ) of the orbitals in the n = 4 principal level? How many n = 4 orbitals exist?
Quantum Numbers II (SquareCap #2-4)
Solution
Choice ( d ) is erroneous because, for l = 1, the possible values of ml are only –1, 0, and +1.
These sets of quantum numbers are each supposed to specify an orbital. Select all sets that are invalid quantum numbers. a. n = 3; l = 0; ml = 0 b. n = 2; l = 1; ml = –1 c. n = 1; l = 0; ml = 0 d. n = 4; l = 1; ml = –
11.9, 11.10, and 12.4 – Electron Configuration
- Learning Objectives
- Write electron configurations and orbital diagrams using Pauli Exclusion
Principle, Hund's Rule, and the aufbaugh (Aufbau) principle.
- Identify elements and ions based on their electron configurations and orbital
diagrams.
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11.9, 11.10, and 12.4 – Electron Configuration
describe the energy and
“position” of all electrons in
an atom.
- Electrons exist in the lowest
energy levels first, then fill
higher energy levels in
predictable orders.
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