![Page 1: Periodic Trends Density Atomic and Ionic Radii](https://reader033.vdocument.in/reader033/viewer/2022051503/5a4d1ae57f8b9ab059978c5b/html5/thumbnails/1.jpg)
Chapter 10Periodic Trends
DensityAtomic and Ionic Radii
![Page 2: Periodic Trends Density Atomic and Ionic Radii](https://reader033.vdocument.in/reader033/viewer/2022051503/5a4d1ae57f8b9ab059978c5b/html5/thumbnails/2.jpg)
Density
![Page 3: Periodic Trends Density Atomic and Ionic Radii](https://reader033.vdocument.in/reader033/viewer/2022051503/5a4d1ae57f8b9ab059978c5b/html5/thumbnails/3.jpg)
Density• Iridium (Z = 77) has the highest density.• Why not Meitnerium (Z = 109?)• We can predict that an element is more
dense if it is closer to Iridium.
![Page 4: Periodic Trends Density Atomic and Ionic Radii](https://reader033.vdocument.in/reader033/viewer/2022051503/5a4d1ae57f8b9ab059978c5b/html5/thumbnails/4.jpg)
Density
![Page 5: Periodic Trends Density Atomic and Ionic Radii](https://reader033.vdocument.in/reader033/viewer/2022051503/5a4d1ae57f8b9ab059978c5b/html5/thumbnails/5.jpg)
Effective Nuclear Charge (Zeff)
• The effective nuclear charge (Zeff) of an atom is basically how well it is able to hold on to its most loosely held electron.
![Page 6: Periodic Trends Density Atomic and Ionic Radii](https://reader033.vdocument.in/reader033/viewer/2022051503/5a4d1ae57f8b9ab059978c5b/html5/thumbnails/6.jpg)
Atomic radius (radii)
• The atomic radius is essentially the size of an atom.
• The largest atom is Francium (Z = 87).
![Page 7: Periodic Trends Density Atomic and Ionic Radii](https://reader033.vdocument.in/reader033/viewer/2022051503/5a4d1ae57f8b9ab059978c5b/html5/thumbnails/7.jpg)
Atomic Radius
Xylophone monkey
![Page 8: Periodic Trends Density Atomic and Ionic Radii](https://reader033.vdocument.in/reader033/viewer/2022051503/5a4d1ae57f8b9ab059978c5b/html5/thumbnails/8.jpg)
Rank the atoms from smallest to largest
Na, K, O, N
O < N < Na < K
![Page 9: Periodic Trends Density Atomic and Ionic Radii](https://reader033.vdocument.in/reader033/viewer/2022051503/5a4d1ae57f8b9ab059978c5b/html5/thumbnails/9.jpg)
Atomic Radius and Effective Nuclear Charge
• The atomic radius decreases as effective nuclear charge increases.
![Page 10: Periodic Trends Density Atomic and Ionic Radii](https://reader033.vdocument.in/reader033/viewer/2022051503/5a4d1ae57f8b9ab059978c5b/html5/thumbnails/10.jpg)
Effective Nuclear Charge (Zeff)
• The effective nuclear charge of an atom is primarily determined by:
1. The nuclear charge 2. The shielding effect
![Page 11: Periodic Trends Density Atomic and Ionic Radii](https://reader033.vdocument.in/reader033/viewer/2022051503/5a4d1ae57f8b9ab059978c5b/html5/thumbnails/11.jpg)
The Nuclear Charge (Z)
• Example: Carbon vs. Nitrogen• Which atom would you predict to be
smaller?
![Page 12: Periodic Trends Density Atomic and Ionic Radii](https://reader033.vdocument.in/reader033/viewer/2022051503/5a4d1ae57f8b9ab059978c5b/html5/thumbnails/12.jpg)
The Nuclear Charge (Z)Carbon Nitrogen
Both atoms are in the 2nd row (period) of the periodic table. What does this tell us?
![Page 13: Periodic Trends Density Atomic and Ionic Radii](https://reader033.vdocument.in/reader033/viewer/2022051503/5a4d1ae57f8b9ab059978c5b/html5/thumbnails/13.jpg)
The Nuclear Charge (Z)Carbon Nitrogen
The greater the number of protons in the nucleus the greater the effective nuclear charge.
![Page 14: Periodic Trends Density Atomic and Ionic Radii](https://reader033.vdocument.in/reader033/viewer/2022051503/5a4d1ae57f8b9ab059978c5b/html5/thumbnails/14.jpg)
Conclusion: Nitrogen is a smaller atom than carbon because nitrogen has 7 protons to pull in its two levels of electrons whereas
carbon only has 6 protons holding it’s two levels of electrons.
Carbon Nitrogen
For atoms with the same number of energy levels the greater the number of protons in the nucleus the greater the effective nuclear charge.
![Page 15: Periodic Trends Density Atomic and Ionic Radii](https://reader033.vdocument.in/reader033/viewer/2022051503/5a4d1ae57f8b9ab059978c5b/html5/thumbnails/15.jpg)
The Nuclear Charge (Z)
• The size of atoms in the same period (row) is determined by the nuclear charge (number of protons in the nucleus).
![Page 16: Periodic Trends Density Atomic and Ionic Radii](https://reader033.vdocument.in/reader033/viewer/2022051503/5a4d1ae57f8b9ab059978c5b/html5/thumbnails/16.jpg)
Atomic Radius
Xylophone monkey
Nuclear charge explains why atoms get smaller across a period
![Page 17: Periodic Trends Density Atomic and Ionic Radii](https://reader033.vdocument.in/reader033/viewer/2022051503/5a4d1ae57f8b9ab059978c5b/html5/thumbnails/17.jpg)
Shielding Effect.
• The shielding effect is when electrons between the nucleus and the outermost electrons in an atom shield or lessen the hold of the nucleus on the outermost electrons.
![Page 18: Periodic Trends Density Atomic and Ionic Radii](https://reader033.vdocument.in/reader033/viewer/2022051503/5a4d1ae57f8b9ab059978c5b/html5/thumbnails/18.jpg)
Shielding Effect.Why is He smaller than Ne?
HeNe
![Page 19: Periodic Trends Density Atomic and Ionic Radii](https://reader033.vdocument.in/reader033/viewer/2022051503/5a4d1ae57f8b9ab059978c5b/html5/thumbnails/19.jpg)
Conclusion: Neon is larger than helium because it has an increased shielding effect from having two energy levels whereas helium only has one energy level.
HeNe
![Page 20: Periodic Trends Density Atomic and Ionic Radii](https://reader033.vdocument.in/reader033/viewer/2022051503/5a4d1ae57f8b9ab059978c5b/html5/thumbnails/20.jpg)
Atomic Radius
Xylophone monkey
Shielding Effect explains why atoms get larger down a group
![Page 21: Periodic Trends Density Atomic and Ionic Radii](https://reader033.vdocument.in/reader033/viewer/2022051503/5a4d1ae57f8b9ab059978c5b/html5/thumbnails/21.jpg)
Chemical Reactivity
![Page 22: Periodic Trends Density Atomic and Ionic Radii](https://reader033.vdocument.in/reader033/viewer/2022051503/5a4d1ae57f8b9ab059978c5b/html5/thumbnails/22.jpg)
Chemical Reactivity
![Page 23: Periodic Trends Density Atomic and Ionic Radii](https://reader033.vdocument.in/reader033/viewer/2022051503/5a4d1ae57f8b9ab059978c5b/html5/thumbnails/23.jpg)
Chemical Reactivity• Metals tend to lose electrons when reacting.
– Large metal atoms are more reactive.• Nonmetals tend to gain electrons when
reacting.– Small nonmetal atoms are more reactive.
![Page 24: Periodic Trends Density Atomic and Ionic Radii](https://reader033.vdocument.in/reader033/viewer/2022051503/5a4d1ae57f8b9ab059978c5b/html5/thumbnails/24.jpg)
Chemical Reactivity • Metals
increase in reactivity left and down.
• Nonmetals become more reactive up and to the right.
• Most reactive metal is?
• Most reactive nonmetal is?
Fr
F
![Page 25: Periodic Trends Density Atomic and Ionic Radii](https://reader033.vdocument.in/reader033/viewer/2022051503/5a4d1ae57f8b9ab059978c5b/html5/thumbnails/25.jpg)
Ionic Radius
• Ionic Radius is the size of an ion.
![Page 26: Periodic Trends Density Atomic and Ionic Radii](https://reader033.vdocument.in/reader033/viewer/2022051503/5a4d1ae57f8b9ab059978c5b/html5/thumbnails/26.jpg)
Size Change in Ion Formation
![Page 27: Periodic Trends Density Atomic and Ionic Radii](https://reader033.vdocument.in/reader033/viewer/2022051503/5a4d1ae57f8b9ab059978c5b/html5/thumbnails/27.jpg)
Rules for Ionic Radius
• Anions (negative ions) are “always” larger than cations (positive ions).
• Ionic Radius goes by the same rules as atomic radius (ions get larger as we move down and to the left).
• However it is necessary to treat anions and cations separately. (Anions are bigger).
![Page 28: Periodic Trends Density Atomic and Ionic Radii](https://reader033.vdocument.in/reader033/viewer/2022051503/5a4d1ae57f8b9ab059978c5b/html5/thumbnails/28.jpg)
Rank the ions from smallest to largest
K+, N3-, Na+, O2-
Na+ < K + < O2- < N3-
![Page 29: Periodic Trends Density Atomic and Ionic Radii](https://reader033.vdocument.in/reader033/viewer/2022051503/5a4d1ae57f8b9ab059978c5b/html5/thumbnails/29.jpg)
Homework
• Worksheet: Density, Atomic and Ionic Radii