Unit 3: The Electron Cloud and Electromagnetic Radiation

Unit 3 Page 1: Objectives!

Unit 3 Page 2: Electron OrbitalsContent Objective:I can express the arrangement of electrons in atoms through electron configurationsCriteria for Success:I can define orbital.I can explain how electrons are arranged within the electron cloud utilizing the concept of orbitals.

Unit 3 Page 3: The Electron CloudContent Objective:I can express the arrangement of electrons in atoms through electron configurationsCriteria 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.

Unit 3 Page 4-9: Standard Electron and Noble Gas ConfigurationsContent Objective: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 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.

Unit 3 Page 10: Lewis Valence Electron Dot StructuresContent Objective:I can express the arrangement of electrons in atoms through electron configurations and Lewis valence electron dot structures.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.

Unit 3 Page 11: Electromagnetic RadiationContent Objective:I can understand the electromagnetic spectrum and the mathematical relationships between energy, frequency, and wavelength of light.I can calculate the wavelength, frequency, and energy of light using Planck's constant and the speed of light.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.

Unit 3 Page 12: Absorption and Emission SpectraContent Objective:I can express the arrangement of electrons in atoms through electron configurations.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.

Electron OrbitalsUnit 3 Page 2

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.

Is your teacher saying anything about this picture to the right here? You should probably take notes on that. Maybe in this box would be a good place.

The Electron CloudUnit 3 Page 3

Recall:a) The atom has different ___________ _____________. Electrons in the 3rd _________ _________ have more energy AND

are farther from the nucleus than electrons in levels 1 and 2.

b) Within each energy level, there are _____________ that electrons stay in. These ____________ have different general shapes associated with them.

spdf

c) Each __________ (s, p, d, f) has a corresponding number of ____________ that are oriented around the nucleus on the axes.

d) Each ______________ holds AT MOST 2 electrons.

With all of this in mind, we have a few systems that we can use to describe where an electron is within an atom, and how the electron is moving around. These systems are really just different ways of formatting all the same information. We are going to learn to use these systems first, and then we will recap how the systems work and give some vocabulary to it all at once.

The chart below is just the way we are going to start learning this information. We will actually keep coming back to this chart as we gradually add more information to our knowledgebase.

There are two things that it will be helpful to know before we start filling out the chart. Notice that some parts are already highlighted for you! That is because this is VERY IMPORTANT VOCABULARY.

A. Rules Governing How Electrons Fill Orbitals1. The ________________________ _______________________ principle states that it is impossible to determine simultaneously both the position and the velocity of an electron or any other particle. (Meaning you can’t know both WHERE IT IS and HOW IT’S MOVING.) Despite this, we are able to determine the probable location of an electron and determine how electron orbitals are filled, using some rules.2. The _____________________ __________________________ principle states that no two electrons can be in the same place as each other and moving the same way at the same time. (Later, we will learn that this will also mean they cannot have an identical set of quantum numbers.)

I know there’s a lot of information here, but try to keep it all in mind! Here we go…

Element Orbital Notation Quantum Numbers

H1 electron

Electron Configuration: _______________________

Noble gas configuration: ______________________

n =

l =

ml =

ms =

 He2 e-

Electron Configuration: _______________________

n =

l =

ml =

ms =

Noble gas configuration: ______________________

Remember the Pauli Exclusion Principle?Two electrons cannot be in the same place and moving the same way at the same time! So if two electrons share an orbital, they must be moving opposite ways!!WHY???Electrons that share an orbital are stuck in a small space together. But, they are still trying to repel each other

because their charges are the same! The most they can do to avoid each other is to __________ in ______________

________________. So if one is spinning “clockwise” (usually an _____ arrow), the next has to spin “counterclockwise”

(usually a _____ arrow). Two electrons in the same orbital can never spin in the same direction, so two arrows in the

same blank can never point the same way!

Li3 e- Electron Configuration:

_______________________

Noble gas configuration: ______________________

n =

l =

ml =

ms =

Na____ e-

Electron Config: ____________________________

Noble gas config: ___________________________

n =

l =

ml =

ms =

Why don’t the electrons fill the p orbitals by sharing them first? Why do they go to their own orbital?

Think about electrons. What are the charges of electrons? _______________

If you put two electrons near each other, what will they do to each other? _______________

So if you try to put two electrons into an orbital together, they will try to push each other out! And if there is somewhere else for an electron to go without having to gain energy, that electron will move!

So if there are empty p orbitals, the electrons push each other into the empty ones before they end up sharing! There is a name for this!

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.

We’re ready to talk about ml now! Quantum number ml tells you which orbital the electron is in!s ____

p ____ ____ ____

d ____ ____ ____ ____ ____

f ____ ____ ____ ____ ____ ____ ____

Let’s go back and fill in all the ml from above.

 S_____ e-

Electron Config:Noble gas Config:

n =

l =

ml =

ms =

Cl_____ e-

n =

l =

ml =

ms =

e- config:noble gas config:

Sc_____ e-

e- config:noble gas config:

n =

l =

ml =

ms =

Ti____ e-

e- config:noble gas config:

n =

l =

ml =

ms =

Notice: we always start at 1s every time we fill electrons. 2. The _____________ principle states that an electron will occupy the lowest-energy orbital that can receive it.

Quantum Numbers: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.

B. Representing Electron Configurations in Orbital Notation1. The arrangement of electrons in an atom is known as the atom’s _______________________________ ______________________________. One type of electron configuration is ______________________ _____________________________ .

Standard Electron ConfigurationsA. Standard electron configurations eliminate the __________ and ____________ of orbital notation.

1. The number of electrons in a sublevel is shown by adding a _______________.

(l) Orbital Type

0 s1 p2 d3 f

1s2

Noble Gas ConfigurationUnit 3 Page 9

Noble Gas Electron ConfigurationsA. 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.

Go back in and do the noble gas configurations in the chart above!

And now, let’s do some special exercises.

1. a. Write the electron and noble gas configurations for Mo WITHOUT doing the orbital notation!

b. Write the quantum numbers for Mo!

2. What is the noble gas configuration of Ta?

3. What is the noble gas configuration of Bi?

4. What element am I talking about?a. n = 4 b. n = 5 c. n = 1 d. n = 5

e. n = 3l = 3 l = 1 l = 2 l = 2 l = 1ml = -2 ml = 0 ml = 0 ml = -2

ml = +2ms = -½ ms = +½ ms = -½ ms = -½ ms = +½

5. How can you tell how many valence electrons are in an element from:a. The periodic table?b. An orbital diagram?c. Electron configuration?d. Noble gas configuration?e. Quantum numbers?

Lewis Valence Electron Dot StructuresUnit 3 Page 10

Lewis Valence Electron Dot StructuresA. 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 one of your element symbol and, moving clockwise, put a ______ every 90° until the number of valence electrons present in the atom is achieved.

Go back to your chart from the other day and draw in Lewis Structures next to the orbital diagrams, electron configurations, etc. Then, if you need more practice, try the ones below.

Electromagnetic RadiationUnit 3 Page 11

Development of a New Atomic ModelA. 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 f3. 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.

Element Symbol Group Number Number of Valence Electrons

C

F

H

Al

Mg

Ne

Absorption and Emission SpectraUnit 3 Page 12

Absorption and Emission of Energy by ElectronsA. 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.

Emission Spectrum of Hydrogen

E. When an electric current is passed through a glass tube that contains hydrogen gas at low pressure the tube gives off blue light. When this light is passed through a prism (as shown in the figure below), four narrow bands of bright light are observed against a black background.

Each band is a different color than the other, corresponding with the wavelength and frequency of the light as it fell from an excited state back to ground state.

The four bands of light will always be the same for hydrogen, 100% of the time. Meanwhile, all other elements also have their own emission spectra that are the same for that element all the time.

No two elements will EVER have _____________ emission spectra. This means that emission spectra can be used to ____________ what kind of element(s) is/are in a sample!

Unit 3 Appendix—Polyatomic IonsUnit 3 Pg 13

Recall that a polyatomic ion is a group of elements, usually nonmetals, that are covalently bonded together. Due to unequal sharing of electrons, the overall group of elements will carry a charge. In most cases, the charges are negative, but sometimes they are positive.

This year, you will be required to memorize a list of polyatomic ions—both their formulas, and their ions. Each six weeks, there will be certain ions we memorize. You will be expected to know all old ions from previous six weeks as well as the new ions we add on each cycle.

For the 2nd six weeks, you STILL need to have all the 1 st Six Weeks ions memorized (your “Nick the Camel” ions).

Additionally, you will also need to memorize the following other ions:

Ion Name Formula Ion Name Formula

periodate hypoiodite

perchlorate hypochlorite

perbromate hypobromite

Notice a pattern between the “per-ate”s and “hypo-ite”s of similar ions, especially compared to ions you already know.

For instance, write the formulas of perbromate, bromate, bromite, and hypobromite.

perbromate: ________ bromate: ________ bromite: ________ hypobromite: ________

Compare the above four formulas. What pattern do you see?

I notice that _______________________________________________________________________________________.

This pattern holds true for all of the “per-ates” and “hypo-ites”! So as long as you can use the sentence, you can figure out these new ions!

Nick the Camel ate an Icky Clam for Supper in Phoenix with his BrosHow does a “per-ate” compare to an “-ate” ion: ___________________________________________________________

How does a “hypo-ite” compare to an “-ite” ion: ___________________________________________________________

A general ranking: per________ate:

________ate:

________ite:

hypo________ite:

Unit 3 Appendix—Second Six Weeks QuizzesUnit 3 Pg 14

In Pre-AP Chemistry, we will take only two quizzes in class every Six Weeks. These two quizzes will both cover the same material as each other.

This material is not necessarily information that we are covering in the current unit. Rather, the materials on the quizzes will be content that the Pre-AP teachers feel is important for you to know and continue practicing all year long. These quizzes will build on each other as far as what they cover from one Six Weeks to the next.

We have a system in Pre-AP Chemistry to make retesting easier:

If you pass the first quiz of the six weeks (grade of 70+), great! Just make sure you study and also pass the second quiz. If you fail the first quiz of the six weeks (grade <70), make sure you study hard for the second quiz!

o If you pass the second quiz, we will count that as your retest for the failed quiz grade! So if you get a 30 on the first quiz and a 70 or higher on the second quiz, you will keep your second quiz

grade AND your first quiz grade will go up to a 70! If you don’t pass the second quiz but score higher than your original score, your first quiz grade will raise

to whatever you got on the second quiz. So if you got a 30 on the first quiz and a 60 on the second quiz, your first grade will still go up to a 60.

o If you fail the second quiz, you will have to come in before or after school to take a requiz. Use the testing schedule on my website (also posted outside my classroom) to know which room to go to

and when (every teacher will have a copy of the requiz for you to take, no matter when you go in) If you pass the requiz, all failing quiz grades you have will be raised to 70s.

Please note: if you memorize the sentence wrong, you will not be able to properly determine the ion formulas! For instance, if you spell “Phoenix” with the wrong number of vowels, or if you accidentally memorize it as “icky clams” instead of “AN icky clam,” or if you mistake Clam as standing for carbonate when it actually stands for chlorate.

If you fail the requiz, your top 2 out of the 3 grades will go on your report card. As before, if you fail the requiz but score higher than either of your original quiz grades, your original

grades will go up to whatever you made on the requiz.Feel free to ask any questions about this system that you may have.

Second Six Weeks Quiz Material that YOU NEED TO STUDY:

Everything from First Six Weeks Quizzes, including but not limited to: Sig Fig measurements and calculations

Be able to look at a number and figure out how many significant figures it has Be able to look at a measurement and figure out how many significant figures it should be

written with Be able to do a calculation and figure out how many significant figures the answer should

have, and round the answer appropriately Scientific Notation—Be able to put a number into or out of scientific notation Conversions and the Metric System— Be able to convert metric units from one prefix to another, or

to a base unit All the First Six Weeks ions (use Nick the Camel to figure out the ions and formulas (including

charges) (See Pg 16 of Unit 1—Appendix for Unit 1) Moles

Convert particles (atoms, molecules, etc.) to moles and/or moles to particles Convert grams to moles and/or moles to grams Convert particles to grams and/or grams to particles

NEW Ions (See Unit 2 Appendix—Unit 2-5 Pg 4)—all the per-ates and hypo-ites

Unit 3 Appendix—More Moles PracticeTry these mole problems so you don’t forget how to do them! Moles will be on your quizzes for the rest of the year!

1. Find the number of moles of argon in 452 g of argon.

2. Find the grams in 1.26 x 10-4 mol of C.

3. Find the mass in 2.6 mol of lithium.

4. How many atoms are in 0.750 moles of zinc?

5. How many molecules are in 0.400 moles of N?

6. How many moles are 1.20 x 1025 atoms of phosphorous?

7. Find the mass, in grams, of 1.00 x 1023 molecules of Zr.

8. How many particles are there in 1.43 g of neon?