Proton = + charge Neutron = neutral charge Electron = - charge.
Section 3: Periodic Trends. Nuclear Charge Nuclear charge is the pull that an electron “feels”...
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Transcript of Section 3: Periodic Trends. Nuclear Charge Nuclear charge is the pull that an electron “feels”...
![Page 1: Section 3: Periodic Trends. Nuclear Charge Nuclear charge is the pull that an electron “feels” from the nucleus. The closer an electron is to the nucleus,](https://reader036.fdocuments.in/reader036/viewer/2022062323/5697c0101a28abf838ccaee7/html5/thumbnails/1.jpg)
Section 3: Periodic Trends
![Page 2: Section 3: Periodic Trends. Nuclear Charge Nuclear charge is the pull that an electron “feels” from the nucleus. The closer an electron is to the nucleus,](https://reader036.fdocuments.in/reader036/viewer/2022062323/5697c0101a28abf838ccaee7/html5/thumbnails/2.jpg)
Nuclear Charge
• Nuclear charge is the pull that an electron “feels” from the nucleus.
• The closer an electron is to the nucleus, the more pull it feels.
• As nuclear charge increases, the electron cloud is pulled in tighter.
• Increases across a period.
![Page 3: Section 3: Periodic Trends. Nuclear Charge Nuclear charge is the pull that an electron “feels” from the nucleus. The closer an electron is to the nucleus,](https://reader036.fdocuments.in/reader036/viewer/2022062323/5697c0101a28abf838ccaee7/html5/thumbnails/3.jpg)
Shielding
• As more energy levels are added to atoms, the inner layers of electrons shield the outer electrons from the nucleus.
• Outer electrons are less tightly held.
• Constant across a period.
• Increases down a group.
![Page 4: Section 3: Periodic Trends. Nuclear Charge Nuclear charge is the pull that an electron “feels” from the nucleus. The closer an electron is to the nucleus,](https://reader036.fdocuments.in/reader036/viewer/2022062323/5697c0101a28abf838ccaee7/html5/thumbnails/4.jpg)
Atomic Radius
• Definition: Half of the distance between nuclei in covalently bonded diatomic molecule
![Page 5: Section 3: Periodic Trends. Nuclear Charge Nuclear charge is the pull that an electron “feels” from the nucleus. The closer an electron is to the nucleus,](https://reader036.fdocuments.in/reader036/viewer/2022062323/5697c0101a28abf838ccaee7/html5/thumbnails/5.jpg)
ElectronicStructureof Atoms
Atomic Radius
-due tomore
shielding(more energy levels)
increases d
ow
n a g
rou
p
-due to greater nuclear charge(more protons)
decreases across a period
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Atomic Radius
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Example of Atomic Radius Trend
• Arrange the following elements in order of increasing atomic radii: Cs, F, K, Cl
![Page 8: Section 3: Periodic Trends. Nuclear Charge Nuclear charge is the pull that an electron “feels” from the nucleus. The closer an electron is to the nucleus,](https://reader036.fdocuments.in/reader036/viewer/2022062323/5697c0101a28abf838ccaee7/html5/thumbnails/8.jpg)
ElectronicStructureof Atoms
Cations from metals:e–’s lostpositive (+) chargesmallerouter shell lost
Anions from nonmetals:e–’s gainednegative (–) charge larger less nuclear charge
Ionic Radius
![Page 9: Section 3: Periodic Trends. Nuclear Charge Nuclear charge is the pull that an electron “feels” from the nucleus. The closer an electron is to the nucleus,](https://reader036.fdocuments.in/reader036/viewer/2022062323/5697c0101a28abf838ccaee7/html5/thumbnails/9.jpg)
Ions
• Here is a simple way to remember which is the cation and which the anion:
This is a cat-ion.This is Ann Ion.
He’s a “plussy” cat!
She’s unhappy and negative.
+ +
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Cation Formation
11p+
Na atom
1 valence electron
Valence e- lost in ion formation
Nuclear charge on remaining electrons increases.
Remaining e- are pulled in closer to the nucleus. Ionic size decreases.
Result: a smaller sodium cation, Na+
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Anion Formation
17p+
Chlorine atom with 7 valence e-
One e- is added to the outer shell.
Nuclear charge is reduced and the e- cloud expands.
A chloride ion is produced. It is larger than the original atom.
![Page 12: Section 3: Periodic Trends. Nuclear Charge Nuclear charge is the pull that an electron “feels” from the nucleus. The closer an electron is to the nucleus,](https://reader036.fdocuments.in/reader036/viewer/2022062323/5697c0101a28abf838ccaee7/html5/thumbnails/12.jpg)
Ionic Radius
Notice that the anions are larger than the cations!
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Example of Ionic Radius Trend
• Arrange the following ions in order of increasing ionic radii:
Ca2+, K+, Al3+, S2-, Cl-, Te2-
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ElectronicStructureof Atoms
1. Atoms get ___ down a group due to ___.
A. bigger, greater nuclear charge (protons)
B. smaller, less nuclear charge (protons)
C. bigger, more shielding (levels)
D. smaller, less shielding (levels)
Quick Quiz!
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ElectronicStructureof Atoms
2. Atomic radii ___ across a period due to ___.
A. decrease, greater nuclear charge (protons)
B. decrease, less nuclear charge (protons)
C. increase, more shielding (levels)
D. increase, less shielding (levels)
Quick Quiz.
![Page 16: Section 3: Periodic Trends. Nuclear Charge Nuclear charge is the pull that an electron “feels” from the nucleus. The closer an electron is to the nucleus,](https://reader036.fdocuments.in/reader036/viewer/2022062323/5697c0101a28abf838ccaee7/html5/thumbnails/16.jpg)
ElectronicStructureof Atoms
3. Which of the following has the largest radius?
A. Na
B. Mg
C. K
D. Ca
Quick Quiz. WHY?most
shielding(levels)
least nuclear charge
(protons)
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ElectronicStructureof Atoms
4. Metals tend to ________ electrons to form _________ cations.
A. gain, positive
B. gain, negative
C. lose, negative
D. lose, positive
Quick Quiz.