level 10
AyakoSaso
楼主
54. Which of the following has the highest second ionization energy?
(A) Cl
(B) S
(C) Na
(D) Mg
(E) Al
Explanation
The second ionization energy is the energy needed to remove the second-most loosely held electron. Use the periodic table to write a simplified electron configuration for each element:
Cl [Ne] 3s23p5
S [Ne] 3s23p4
Na [Ne] 3s1
Mg [Ne] 3s2
Al [Ne] 3s23p1
After writing the configurations, it should be easy to tell that the second electron removed from sodium would come from an inner energy level. The closer the electrons are to the nucleus, the harder they are to remove.
115.
Statment I A sample of gas is heated at constant pressure from 200K to 400K and its volume doubles.
BECAUSE
Statement II Each molecule expands to twice its original volume.
I II CE*
F F
F F is not the correct answer. You should have selected T F.
Explanation
Statement I is true. Charles’s law states that as temperature increases, the volume increases when pressure and number of particles are held constant. Gas laws are worked using the Kelvin scale; if the temperature in Kelvin doubles, the volume should also double. Statement II is false. This statement implies that the gas molecule itself changes size—gases are mostly empty space. The space that they must occupy to keep the same pressure must double at the given temperature, but the molecules themselves do not change in size.
Ca, Na, Mg, Zn, Fe, H, Cu, Hg, Ag, Au
58. The element that is the best oxidizing agent is
(A) Ca
(B) Au
(C) H
(D) Fe
(E) Cu
C is not the correct answer. You should have selected B.
Explanation
The best oxidizing agent will be the element that is most easily reduced. Since the elements are listed in decreasing order, Au will be the least reactive, so it should be the most easily reduced. Choice A, Ca, is the most active and will be the most easily oxidized. Choices C–E are all scattered in the activity series and can therefore be easily eliminated.
2011年05月02日 12点05分
1
(A) Cl
(B) S
(C) Na
(D) Mg
(E) Al
Explanation
The second ionization energy is the energy needed to remove the second-most loosely held electron. Use the periodic table to write a simplified electron configuration for each element:
Cl [Ne] 3s23p5
S [Ne] 3s23p4
Na [Ne] 3s1
Mg [Ne] 3s2
Al [Ne] 3s23p1
After writing the configurations, it should be easy to tell that the second electron removed from sodium would come from an inner energy level. The closer the electrons are to the nucleus, the harder they are to remove.
115.
Statment I A sample of gas is heated at constant pressure from 200K to 400K and its volume doubles.
BECAUSE
Statement II Each molecule expands to twice its original volume.
I II CE*
F F
F F is not the correct answer. You should have selected T F.
Explanation
Statement I is true. Charles’s law states that as temperature increases, the volume increases when pressure and number of particles are held constant. Gas laws are worked using the Kelvin scale; if the temperature in Kelvin doubles, the volume should also double. Statement II is false. This statement implies that the gas molecule itself changes size—gases are mostly empty space. The space that they must occupy to keep the same pressure must double at the given temperature, but the molecules themselves do not change in size.
Ca, Na, Mg, Zn, Fe, H, Cu, Hg, Ag, Au
58. The element that is the best oxidizing agent is
(A) Ca
(B) Au
(C) H
(D) Fe
(E) Cu
C is not the correct answer. You should have selected B.
Explanation
The best oxidizing agent will be the element that is most easily reduced. Since the elements are listed in decreasing order, Au will be the least reactive, so it should be the most easily reduced. Choice A, Ca, is the most active and will be the most easily oxidized. Choices C–E are all scattered in the activity series and can therefore be easily eliminated.
![[不要]](/static/emoticons/u4e0du8981.png)