The Electron Cloud
Unit 3 Page 1
Learning Target:
I can express the arrangement of electrons in atoms through electron configurations
Criteria for Success:
I can define orbital.
I can explain how electrons are arranged within the electron cloud utilizing the concept of orbitals.
Notes: Electron Orbitals
A. The electron cloud consists of a complex arrangement of _______________________ within a series of main energy
________________________ and energy ____________________________.
1. Erwin _____________________________ used the hypothesis that electrons have a dual wave-particle nature
to develop wave _________________________ to describe electrons. The solutions to these equations
describe the __________________________ that make up the electron cloud.
2. ________________________, which are three-dimensional regions around the nucleus, indicate the probable
location of the electron.
a. A maximum of _________ electrons can fit in a single orbital.
3. Main energy levels indicate the general amount of __________________ and ___________________ from
the nucleus a given electron in an orbital possesses.
a. Each ______________, or period, on the periodic table indicates a main energy level and the
maximum number of electrons that can occupy that energy level.
4. Energy sublevels indicate the different _____________________ of orbitals that exist within the same main
energy level and these different shapes of electron orbitals are indicated by _______________________.
a. The s orbitals have a _________________ shape and there is only ________ s orbital in any given
main energy level and correspond to the first two columns on the periodic table.
b. The p orbitals resemble _________________ and there are a maximum of __________ p orbitals in
any given main energy level and correspond to the last six columns on the periodic table.
c. The d orbitals often resemble _______________ and there are ___________ d orbitals in any given
main energy and correspond to the transition elements on the periodic table.
d. Orbitals with higher energy than the d orbitals are labeled f, g…and so on in alphabetical order, but
their shapes are _____________________ to represent and are rarely used in general chemistry.
5. The electrons in the outermost energy level, or ______________________ level, are integral in determining
how the atom will react chemically.
a. The _________________ number (column) will help you determine how many valence electrons an
atom has.
The Electron Cloud
Unit 3 Page 3
Learning Target:
I can express the arrangement of electrons in atoms through electron configurations
Criteria for Success:
I can state three rules that explain how electrons fill orbitals.
I can use those three rules to describe the electron configuration for the atoms of any element in orbital notation.
I can relate the number of sublevels to each atom's main energy levels, the number of orbitals per sublevel and per main
energy level.
I can use electron configurations and orbital notation to determine quantum numbers.
How Electrons Fill Orbitals
A. Rules Governing How Electrons Fill Orbitals
1. The ________________________ _______________________ principle states that it is impossible to
determine simultaneously both the position and the velocity of an electron or any other particle. Despite this,
we are able to determine the probable location of an electron and determine how electron orbitals are filled,
using the following rules:
1. The _____________________ __________________________ principle states that no two electrons
can have the same set of four quantum numbers.
(l)
Orbital Type
0
1
2
3
s
p
d
f
a. The __________________________ quantum number (n), indicates the main
energy level. Values of n are positive integers 1, 2, 3, and so on.
b. The ________________________ _________________________ quantum number (l)
indicates the shape of the orbital.
c. The _________________________ quantum number
(ml) indicates the orientation of an orbital around the
nucleus. Can have a value of – l through zero to +l.
d. The _____________________ quantum number (ms)
has only two possible values, + ½ and – ½, because
only two electrons can exist in the same orbital and
indicates one of the two fundamental spin states of an
electron.
2. The _______________________ principle states that an electron will
occupy the lowest-energy orbital that can receive it.
3. ___________________________ rule states that orbitals of equal
energy are each occupied by one electron before any orbital is occupied
by a second electron, and all electrons in singly occupied orbitals must
have the same spin.
B. Representing Electron Configurations in Orbital Notation
1. The arrangement of electrons in an atom is known as the atom’s _______________________________
______________________________. One type of electron configuration is ______________________
_____________________________ .
Standard Electron Configurations
Unit 3 Page 5
Learning Target:
I can express the arrangement of electrons in atoms through electron configurations.
Criteria for Success:
I can describe the electron configurations for the atoms of any element using standard notation.
I can determine the number of electrons, energy levels, and valence electrons for any element on the periodic table.
I can use electron configurations to identify an element by atomic number.
I can use electron configurations and orbital notation to determine quantum numbers.
Standard Electron Configurations
A. Standard electron configurations eliminate the __________ and ____________ of orbital notation.
1. The number of electrons in a sublevel is shown by adding a _______________.
1s2
Guided/Independent Practice
Noble Gas Configuration
Unit 3 Page 7
Learning Target:
I can express the arrangement of electrons in atoms through electron configurations.
Criteria for Success:
I can describe the electron configurations for the atoms of any element using noble gas notation.
I can determine the number of electrons, energy levels, and valence electrons for any element on the periodic table.
I can use electron configurations to identify an element by atomic number.
I can use electron configurations and orbital notation to determine quantum numbers.
Noble Gas Electron Configurations
A. A ________________ _______ configuration is an electron configuration that utilizes a noble gas which has its
____________ level fully occupied.
[He] = 1s2
[Ne] = 1s22s22p6
[Ar] = 1s22s22p63s23p6
[Kr] = 1s22s22p63s23p64s23d104p6
[Xe] = 1s22s22p63s23p64s23d104p65s24d105p6
[Rn] = 1s22s22p63s23p64s23d104p65s24d105p66s24f145d106p6
1. Noble gas configurations are often used to help _____________ the electron configurations of those elements
that contain large numbers of electrons.
Guided/Independent Practice
Lewis Valence Electron Dot Structures
Unit 3 Page 9
Learning Target:
I can express the arrangement of electrons in atoms through electron configurations and Lewis valence electron dot
structures. (6E)
Criteria for Success:
I can use the periodic table to determine how many valence electrons an element has.
I can use a Lewis dot diagram to identify an element.
I can use the periodic table to draw the Lewis valence electron dot structure for an element.
Lewis Valence Electron Dot Structures
A. Lewis _______________ electron dot structures show the symbol of an element and its number of ______________
electrons.
1. ________________ electrons are those electrons in the _________________ energy level of an atom.
2. ________________ electrons are integral in determining how the atom will __________________ react with
other atoms.
B. Use the following steps to draw a Lewis valence electron dot structure.
1. Write the element _______________.
2. Determine the __________ number for the element.
a. The ___________ number indicates the number of ______________ electrons.
3. Start on the ____________ of your element symbol and, moving counter-clockwise, put a ______ every 90°
until the number of valence electrons present in the atom is achieved.
Guided/Independent Practice
Element Symbol
C
F
H
Al
Mg
Ne
Group Number
Number of Valence
Electrons
The Electron Cloud
Unit 3 Page 11
Learning Target:
I can understand the electromagnetic spectrum and the mathematical relationships between energy, frequency, and wavelength of
light. (6B)
I can calculate the wavelength, frequency, and energy of light using Planck's constant and the speed of light. (6C)
Criteria for Success:
I can describe and interpret the electromagnetic spectrum.
I can calculate wavelength, frequency, speed, and the amount of energy of a photon of light.
I can explain the relationships between energy, frequency, and wavelength.
Development of a New Atomic Model
A. A new atomic model evolved as a result of the investigation into the absorption and emission of ____________ by
matter.
1. Visible ____________ is a kind of __________________________
__________________, which is a form
of energy that exhibits both wave-like and particle-like behaviors as it travels through space.
a. Visible light can behave like a _______ characterized by the measurable properties of ____________
and ______________.
1. _______________ (λ) is the distance between corresponding points on adjacent waves.
2. ________________________ (f) is defined as the number of waves that pass a given point in
a specific time, usually one second (Often measured in hertz, Hz).
3. The wavelength and frequency for light waves can be related mathematically in the following
way:
c= f λ
b. Visible light can behave like a stream of particles or ____________. A ____________ is a particle of
electromagnetic radiation having zero mass and carrying a specific amount of energy.
1. The ________________________ effect is evidence that light behaves as stream as particles.
2. Max Planck suggested and Albert Einstein elaborated on the following formula when
describing the relationship between frequency and the ___________ of energy of a photon.
Ephoton = h f
3. A ________ is a specific amount of energy proportional in size to the frequency of the
radiation it represents.
B. Scientists use this understanding of ____________ to also describe the properties of the _______________ and their
behavior in the electron cloud.
The Electron Cloud
Unit 3 Page 13
Learning Target:
I can express the arrangement of electrons in atoms through electron configurations. (6E)
Criteria for Success:
I can explain the movement of electrons within atoms as they absorb or emit different amounts of energy.
I can tell the difference between an atom in the ground state and an excited state by the electron configuration.
Absorption and Emission of Energy by Electrons
A. Atoms will exist in two states in relation to ___________.
1. The lowest potential energy state of an atom is its ____________ _____________.
2. A state in which an atom has a higher potential energy than it does in its ground state is an
__________________ _________________.
B. Electrons can move to a higher energy orbital by gaining a specific amount, or _______________, of
__________________.
C. When electrons fall back from the excited state a specific amount or, a ______________ , of _____________ is
released equal to the energy difference between the two orbitals.
D. The ____________________ _________________ of an element is the relative intensity of each frequency of
electromagnetic radiation emitted by the atom as the atom’s electrons return from the excited state to the ground
state.