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Ionization Energy and Electron Affinity Problems

Of the choices below, which gives the order for first ionization energies?

a. Ar > Cl > S > Si > Al
b. Cl > S > Al > Si > Ar
c. Al > Si > S > Cl > Ar
d. Cl > S > Al > Ar > Si

Which of the following has the largest second ionization energy?

a. Na
b. Si
c. Mg
d. P
e. Al

Which equation correctly represents the first ionization of aluminum?

a. Al(g) -> Al-(g) + e-
b. Al+(g) + e- -> Al(g)
c. Al(g) + e- -> Al-(g)
d. Al(g) -> Al+(g) + e-
e. Al-(g) -> Al(g) + e-

In general, as you go across a period in the periodic table from left to right: (1) the atomic radius __________; (2) the electron affinity becomes __________ negative; and (3) the first ionization energy ___________.

a. increases, increasingly, decreases
b. increases, increasingly, increases
c. decreases, decreasingly, increases
d. decreases, decreasingly, decreases
e. decreases, increasingly, increases

Which of the following correctly represents the electron affinity of bromine?

a. Br+(g) + e- -> Br(g)
b. Br2(g) + 2 e- -> 2 Br-(g)
c. Br(g) -> Br+(g) + e-
d. Br(g) + e- -> Br-(g)
e. Br2(g) + e- -> Br-(g)

Which of the following is not a characteristic of metals?

a. Ductility
b. Low ionization energies
c. Acidic oxides
d. Malleability
e. These are all characteristics of metals.

Alkali metals tend to be more reactive than alkaline earth metals because ____________.

a. alkali metals have greater electron affinities
b. alkali metals have lower melting points
c. alkali metals have lower ionization energies
d. alkali metals are not more reactive than alkaline earth metals
e. alkali metals have lower densities

Oxides of the active metals combine with water to form ____________.

a. metal hydrides
b. hydrogen gas
c. metal hydroxides
d. oxygen gas
e. water and a salt

The series that correctly lists from left to right a halogen, an alkaline earth metal, a transition metal, and an active metal is __________.

a. Br, Ba, Cr, Na
b. O, Ca, Ce, Al
c. F, Sr, Fe, Sn
d. S, Sr, Si, Sn
e. Cl, K, V, Mg

Hydrogen is unique among the elements because ____________.

1. It has only one valence electron.
2. It is the only element that can emit an atomic spectrum.
3. Its electron is not at all shielded from its nucleus.
4. It is the lightest element.
5. It is the only element to exist at room temperature as a diatomic gas.

a. 1, 2, 3, 4, & 5
b. 1, 3, & 4
c. 1, 2, 3, & 4
d. 2, 3, & 4
e. 3 & 4

Of the ions below, only _____ has a noble gas electron configuration.

a. K-
b. I+
c. O2+
d. S3-
e. C1-

Solution Preview

Of the choices below, which gives the order for first ionization energies?

a. Ar > Cl > S > Si > Al <----------------
b. Cl > S > Al > Si > Ar
c. Al > Si > S > Cl > Ar
d. Cl > S > Al > Ar > Si

First Ionization Energies List....
Ar 1520.6 KJ/mol
Cl 1251.2 KJ/mol
S 999.6 KJ/mol
Si 786.5 KJ/mol
Al 577.5 KJ/mol

http://www.webelements.com/webelements/scholar/elements/aluminium/electronic.html

Though you really do not need the actual energies to predict this result. Remembering the Ar has filled shells it is going to be the least energetically favored "like the least" in losing an electron through ionization of the group so a) is the only choice for the groupings. The order in a): each element moves further and further from the stability of the [Ar] electron configuration such that ionization is more and more favored as is evident from the actual values listed. Look the ionization potential of Mg: 737.7 KJ/mol. Ionization of Al to the Mg configuration results in actually a more stable [Ne]3s2 over the [Ne]3s23p1 configuration which is less stable than the paired electron configuration of [Ne]3s23p2.

Which of the following has the largest second ionization energy?
a. Na <-------------
b. Si
c. Mg
d. P
e. Al

Second ionization energy, means it is going to go form a first excited ionization state by losing an additional electron through ionization to a state with two less electrons than the ground state.
Na [Ne]3s1 4562.0 kJ/mol <----------------
Si [Ne]3s23p2 1577.1 kJ/mol
Mg [Ne]3s2 1450.7 kJ/mol
P [Ne]3s23p3 1907.0 kJ/mol
Al [Ne]3s23p1 1816.7 kJ/mol

Double ionized state of Mg is [Ne] electron configuration with the greatest stability so I expect this to have the least second ionization energy. The ...

Solution Summary

This solution provides answers to each question along with descriptions regarding how the answer was chosen. A reference is also included to help understanding of the problem.

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