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AP Chem CatalystAP Chem Catalyst AP Chem CatalystAP Chem CatalystCatalyst QuestionsCatalyst Questions To Do & Homework To Do & Homework
Why do you think lithium and potassium react so differently with water, even though they are from the same family of the periodic table?
Why do you think lithium and potassium react so differently with water, even though they are from the same family of the periodic table?
Remind me to pass back your MC and FRQs After school, today, mandatory tutoring for those that didn’t attend last Friday. RETAKES: This Friday after school. Shorter version of the test.
Remind me to pass back your MC and FRQs After school, today, mandatory tutoring for those that didn’t attend last Friday. RETAKES: This Friday after school. Shorter version of the test.
Please create 5 tabs on your folders where you’re temporarily putting stuff. Organization is very important for when we review in April.
1) Notes 2) Outlines 3) Tests/Quizzes/Study Guides 4) Problem Sets 5) Classwork
Please create 5 tabs on your folders where you’re temporarily putting stuff. Organization is very important for when we review in April.
1) Notes 2) Outlines 3) Tests/Quizzes/Study Guides 4) Problem Sets 5) ClassworkB
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Flame Test Lab (Lab Flame Test Lab (Lab NB)NB)
• Lab Notebook Set Up (Informal Report)
• Title o Should summarize overall lab
• Introduction (~2 sentences)o Restate the purposeo What are we expected to do (one sentence) o Restate chemical equations, formulas, or concepts.
• Materials and Methods (2 sentences)o Brief explanation of the lab procedure
• Results (1 table)o You DON’T interpret the data in this section!
• Analysis/Conclusion (~4 sentences) Restate data (This is your evidence)o Explain the meaning of the data o Restate the purpose and elaborate based on your data o How does this related to frequency, wavelength, energy. What is the formula that
shows this relationship? What do the colors mean? Visible light? Why is light emitted? Who postulated this?
BozemanBozeman• http://www.bozemanscience.com/ap-chem-006-pe
riodicity• Listen to his video and take thorough notes on
what he is saying ON the concept map he made.
• Once you’re done start on test corrections (HW) or your informal report for today’s lab (HW)
2.12.1Periodic TrendsPeriodic Trends
AP Chem CatalystAP Chem Catalyst AP Chem CatalystAP Chem CatalystCatalyst QuestionsCatalyst Questions To Do & Homework To Do & Homework
1) Which of the following states that no two electrons in an atom can have the same set of quantum numbers? A) Hunds Rule B)Heisenbergs principle C)Aufbau rule D)The de broglie hypothesis E)None of the above
2) This element may form a compound with the formula KXO4
A) Se B) Cl C) P D) Na E) Xe
1) Which of the following states that no two electrons in an atom can have the same set of quantum numbers? A) Hunds Rule B)Heisenbergs principle C)Aufbau rule D)The de broglie hypothesis E)None of the above
2) This element may form a compound with the formula KXO4
A) Se B) Cl C) P D) Na E) Xe
Take out your notes from last weekRewrite the old notes into the new notes.
Take out your notes from last weekRewrite the old notes into the new notes.
Please create 5 tabs on your folders where you’re temporarily putting stuff. Organization is very important for when we review in April.
1) Notes 2) Outlines 3) Tests/Quizzes/Study Guides 4) Problem Sets 5) Classwork
Please create 5 tabs on your folders where you’re temporarily putting stuff. Organization is very important for when we review in April.
1) Notes 2) Outlines 3) Tests/Quizzes/Study Guides 4) Problem Sets 5) ClassworkB
ind
er
Bin
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r
Memorize!
Increasing Atomic Size or Atomic Radius
Increasing Ionization Energy,
and Electronegativity
Quickwrite: Quickwrite: Why do you think Why do you think radius increases radius increases
toward A) left toward A) left and B) downand B) down
The size (radius) of an atom shrinks as you go to
the right of the periods/rows and down the
groups/columns.
Remember:
Periods are horizontal rows.
Groups or families are vertical columns.
Atomic Radius – size of an atom from the nucleus to the valence electrons.
Trends in SizeTrends in Size
The size of an atom is due to
the size of the electron cloud
(electron density).
Know that there are
attractions between the
electrons and protons in the
nucleus known as the effective
nuclear charge (Zeff)
Zeff takes into account: Electron-electron repulsion Electron shielding or screening from core electrons
Trends in SizeTrends in Size
Across:
Atoms get smaller because
there are more protons
pulling the electrons toward
itself making the size of the
atom smaller.
Down:
The atoms get larger
because there are more
layers of electrons; more
orbits.
Each layer is further from
the nucleus so there is less
attraction between the
nucleus and the valence
electrons.
More protons
More layers
Coulomb’s LawCoulomb’s Law• The attractive force (Fa) felt by two
charged objects is directly related to the size of the charge and inversely related to the distance b/w the objects.
• Directly: increasing charge, increases Fa
• Indirectly: Increasing distance, decreases Fa
• If the charge inside the nucleus increases (more protons), then Fa increases.
• But if the electrons are further apart (distance increases) then Fa decreases
F = k Q1Q2 r2
Q is charge, r is radius and k is some constant
Electron ShieldingElectron Shielding• In elements with many electrons, inner electrons
(core electrons) shield the valence electrons. • This causes valence electrons to be LESS
attracted to the nucleus. • Therefore, the core electrons act to shield the
valence electrons from the full positive charge of the nucleus.
Predict the TrendPredict the Trend• Do you think the Zef increases or decreases down
a group on the PT? • What about going across a period left to right? • Justify you answer with evidence and include this
idea of electron shielding.
Trends in ZTrends in Zefef• The further away from the nucleus, the less the
nuclear charge is “felt” so Zef decreases down the PT.
• As you continue across a period, there are no new core electrons (electron clouds) but there is a stronger positive charge in the nucleus therefore, Zef increases going across a period.
Sizes of Sizes of IonsIonsEach time an e- is
removed, the ion becomes
smaller because the
nucleus can now further
pull electrons toward itself
making the ion smaller.
Atoms that gain electrons
become larger because
the more electrons, the
harder it is for the protons
in the nucleus to attract
those extra electrons.
Electron Shielding Effect Electron Shielding Effect – Valence – Valence electrons become shielded from the electrons become shielded from the positively charged nucleus as you add positively charged nucleus as you add more electron orbits. This effect allows the more electron orbits. This effect allows the atomic radius to increase moving down atomic radius to increase moving down the periodic table.the periodic table.
Ca atom Ca2+ ion Cl atom Cl– ion
20 p+
20 e–
20 p+
18 e–
17 p+
17 e–
17 p+
18 e–
Ca Ca2+ Cl Cl–
Ionic RadiusCations are _______ than parent atoms;anions are ______ than parent atoms.
EX. Compare the sizes of Fe, Fe2+, and Fe3+.
Then compare Br with Br–.
smallerlarger
Fe > Fe2+ > Fe3+
Br– > Br
Class ExampleClass Example• Arrange Na+, K+, and K in order of increasing
atomic radius.
Example - Example - Isoelectronic Isoelectronic
• Rank the ions K+, Ca2+, Cl - and S2- in order of increasing size.
• Do they all have the same # of electrons? • Isoelectronic – same # of electrons • Sizes decrease as nuclear charge (atomic #)
increases. • Based on this, rank the elements. It’s hard to rank
based on the trend in this situation.
Agree or Disagree?Agree or Disagree?1. Coulombs law says that as you pull charges away
from one another, the attractive force increases?2. The effective nuclear charge describes the
attraction b/w the nucleus and electron of interest3. Effective nuclear charge decreases down a group
b/c there are more electrons. 4. Effective nuclear charge increases across a period
b/c the nucleus gets more positive. 5. The ionic radius is always larger than the atomic
radius for a given atom.
6. The following are arranged from smallest to largest radius? Se < Se2- < Te2-
7. The following are arranged from largest to smallest radius: Co3+, Fe2+, Fe3+
8. The attraction between the valence electrons and the nucleus can be weakened by both electron shielding and electron electron repulsion. .
QuickwriteQuickwrite• Based on the
circles, why do the 1s electrons experience a linear increase in Zeff?
• But based on the triangles, why do the valence electrons change from higher to lower after the noble gas configuration?
Ionization Ionization EnergyEnergy
This is the amount
energy needed to
remove an electron.
It is easier to remove
an electron from a
larger atom because
the electron is farther
from the nucleus and
feels less attraction.
If it’s easy to
remove an e, would
there be a high or
low IE?
Coulombic attraction depends on…
2– 2+
2+ 2– 1–
2–
1+
2+
amount of charge distance between charges
+ + – –
H
He
+ –
+ – + –
As we go , more coulombic attraction, no new energy level, more pull, smaller size
More or less ionization energy?
More or less ionization energy?
ExampleExample• Order the elements from smallest to largest IE:
potassium, cesium, lithium.
Try on your own, then Try on your own, then talk:talk:
• Order the elements from largest to smallest IE: Fluorine, Carbon, Oxygen.
1. Use academic language2. Use your notes 3. Do NOT use your peers for this. 4. Learning occurs when you do
three things: 1. Practice 2. Identifying gaps in knowledge3. Fill those gaps! Use academic language and
be precise.
Check for Understanding: Socrative: Narez 2015
Electron Configuration Electron Configuration of Ions of Ions
• Write the electron configuration for Lithium
• Let’s say you ionize the lithium how would the electron configuration look like now?
(continued)(continued)• Write the CONDENSED electron configuration
for Iron (Fe)
• How would the Condense EC look like for Fe2+?
• New rule: when removing electrons, they are always removed first from the occupied orbitals having the largest principal quantum # (n).
0.77 + 1.14
The distance between bonded nuclei can beapproximated by adding radii from both atoms.
Example: Bonding atomic radii are as follows for carbon and bromine, what is the distance between bonded C and Br nuclei?
So the approximate distance betweenbonded C and Br nuclei = = 1.91 Å
C = 0.77 Å, Br = 1.14 Å
r rd
What is Bond Length?What is Bond Length?
Based on what you know about Based on what you know about ZZefef, predict the trend for bonding , predict the trend for bonding
atomic radius (bond length) atomic radius (bond length) below using arrowsbelow using arrows
What’s odd about this? What’s odd about this? Why does that happen?Why does that happen?
Note: all ionization energies for atoms are positive; energy must be absorbed to remove an electron
Another way of seeing data. On the AP test, you will see tons of graphs and data tables and you must use what you know to explain certain observations or trends.
Another way of seeing data. On the AP test, you will see tons of graphs and data tables and you must use what you know to explain certain observations or trends.
ElectronegativityElectronegativity
ElectronegativityElectronegativity• Electronegativity is the measure
of the ability of an atom to attract electrons.
Electronegativity TrendsElectronegativity Trends• As you go up a group, the
electronegativity of an element increases.
• As you go across a period towards the right, the electronegativity of an element increases.
Why Electronegativity Decreases Why Electronegativity Decreases Down a GroupDown a Group
• As you go down a group more orbits are added.
• Electron Shielding – Valence electrons become shielded from the positively charged nucleus as you add more orbits.
• Electroneg. decreases because there is a decreased ability of the nucleus to attract electrons because of larger distance.
Why Electronegativity Why Electronegativity Increases Across a PeriodIncreases Across a Period
• As you move to the right, you add more protons.
• The more protons, the attracted the electrons to the nucleus so it’s harder for electrons to be removed so elements must have a high electronegativity as you move to the right.
By yourself, then By yourself, then partner talk:partner talk:
• Order the elements from smallest to largest electronegativity: oxygen, beryllium, lithium,
Try againTry again• Order the elements from largest to smallest
electronegativity: chlorine, bromine, fluorine
Electron AffinityElectron Affinity• Gaining of electrons to form anions. • Energy change that occurs when an electron is
added is called the electron affinity, which measures the attraction (affinity) of the atom toward wanting more electrons.
• Energy is usually released when electrons are added (negative)
• Addition of electron to chlorine Cl (g) + e- Cl- (g) ΔE = -350 kJ/mol
Starting what you end with
Memorize!
Increasing Atomic Size or Atomic Radius
Increasing Ionization Energy,
and Electronegativity
Electron affinity
Facts to Remember for Facts to Remember for Lesson 2.2Lesson 2.2
NonmetalsRight side of staircase Insulators (trap heat/electricity; no transfer)Gain electrons to form anions. “Bond” with metals to form ionic bondsBond with other nonmetals to form covalent bonds or molecules/compoundsFound on the “p” blocksNaming covalent (nonmetals) compounds require prefixes!
Metals Good conductors (transfer heat/electricity) Found left side of PTLose electrons to form cations. Bond with nonmetals to form ionic bonds (salts, electrostatic attractions; require criss crossing when finding ionic formulas, never use prefixes in naming) Found on the “s” and “d” blocks
Dear Mr. Narez
Mr. Narez fell down the stairs, hit his head on the wall and experienced memory loss. He forgot what he knew about periodic trends such as atomic radius (size), ionization energy and electronegativity. You are to teach Mr. Narez all of this in detail so we can finish the unit. The requirements of the letter are found on the right side:
Dear Mr. Narez
Mr. Narez fell down the stairs, hit his head on the wall and experienced memory loss. He forgot what he knew about periodic trends such as atomic radius (size), ionization energy and electronegativity. You are to teach Mr. Narez all of this in detail so we can finish the unit. The requirements of the letter are found on the right side:
Criteria for Success: What is atomic radius?What is EN, IE, EA?Why does size decrease moving to the right of the PT?Why does size increase going down? Why does EN and IE increase going up? If EN goes up, why must IE increase too?When do JUMPS in ionization energy occur? Why?Place this INSIDE your writing porfolio.
If you have a what, make sure you elaborate with a WHY. Throw in some pictures if you can.
Criteria for Success: What is atomic radius?What is EN, IE, EA?Why does size decrease moving to the right of the PT?Why does size increase going down? Why does EN and IE increase going up? If EN goes up, why must IE increase too?When do JUMPS in ionization energy occur? Why?Place this INSIDE your writing porfolio.
If you have a what, make sure you elaborate with a WHY. Throw in some pictures if you can.
Plagiarism by copying straight from a website or your teacher’s notes will result in an NP
Plagiarism by copying straight from a website or your teacher’s notes will result in an NP
Quiz, Quiz, Trade Quiz, Quiz, Trade • Step 1: Form an outer and inner circle. • Step 2: People on the outside will rotate to the
left upon sound of a bell. • Step 3: Ask Question, if time permits, other
person asks question. • Step 4: Quiz, rotate, quiz, rotate, trade
• Don’t just give out the answer. • Ask probing questions; give hints. • Use the periodic table/illustrations
Exit TicketExit Ticket1. Define ionization energy.2. Define electronegativity.3. Order from largest to smallest electronegativity: Ca, Se, Ni 4. Order from smallest to largest atomic radius: O, Po, S 5. What two ideas affect effective nuclear charge, Zeff
