Q: Which of the following is the correct ground-state electron configuration for the element with $$Z = 108$$?

$$[\text{Rn}]7s^2$ 5f$$^{14}$$ 6d^6$

Q: For the element vanadium (V), what is the electron configuration and the number of valence electrons in a neutral atom?

$$[\text{Ar}]4s^2$ 3d^3$, 5 valence electrons

Q: Which of the following options shows the isoelectronic ions in order of decreasing radii?

$$\text{S}^{2-} \u003e \text{Cl}^- \u003e \text{Ar}$$

Question 1

A sample of an unknown element emits light with a frequency of $$1.311 	imes 10$$^{15}$$ Hz. Using c = 3.00$$ 	imes $$10^8 m/s$$, what is the characteristic wavelength (in nm) of this emission, and which element is it most likely to be if the options are: Al (396.152 nm), As (189.042 nm), Ca (422.673 nm), Cd (228.802 nm), Cr (267.716 nm), Cu (324.754 nm), Fe (259.652 nm), Hg (253.652 nm)?

Accepted Answer

Cd, 229 nm

Question 2

Which of the following statements about kinetic and potential energy is correct?

Accepted Answer

Kinetic energy is due to the motion of an object, while potential energy is due to the position or place of an object.

Question 3

Which of the following reactions will have $$\Delta H$$ greater than $$\Delta U$$?

Accepted Answer

Reactions where the number of moles of gas increases, such as $$2	ext{Hg}(g) + 	ext{O}_2(g) ightarrow 2	ext{HgO}(g)$$ and $$	ext{CO}(g) + 	ext{H}_2	ext{O}(g) ightarrow 	ext{CO}_2(g) + 	ext{H}_2(g).$$

Question 4

A typical infrared lamp emits 175 watts of energy. Calculate the total energy emitted in kcal by the lamp after 12 hours. ($$1 	ext{ watt} = 1 	ext{ J/s}$$, $$1 	ext{ kcal} = 4184 	ext{ J})$$

Accepted Answer

$$1.8 	imes 10^3$ kcal

Question 5

Which of the following is the correct ground-state electron configuration for the element with $$Z = 108$$?

Accepted Answer

$$[	ext{Rn}]7s^2$ 5f$$^{14}$$ 6d^6$

Question 6

For the element vanadium (V), what is the electron configuration and the number of valence electrons in a neutral atom?

Accepted Answer

$$[	ext{Ar}]4s^2$ 3d^3$, 5 valence electrons

Question 7

Which statement is true based on the radial probability distribution functions for 1s, 2s, and 3s orbitals?

Accepted Answer

The 1s orbital has the most electron density close to the nucleus.

Question 8

Among the following subshells: 3d, 4s, 4p, 4d, 4f, 5s, 5p, 5d, 5f, and 6s, which can contain 4 electrons all with spin quantum number $$m_s = -1/2$$?

Accepted Answer

3d, 4d, and 5d

Question 9

Which of the following options shows the isoelectronic ions in order of decreasing radii?

Accepted Answer

$$	ext{S}^{2-} \u003e 	ext{Cl}^- \u003e 	ext{Ar}$$

Question 10

Is gallium a metal, nonmetal, or metalloid? Why?

Accepted Answer

Based on periodic trends, gallium is a metal because the element above it in the periodic table is a metal.

Question 11

A 15.4 g sample of ethanol ($$C_2H_5OH) is to be $$vaporized at its boiling point. The heat of vaporization is $$38.6 kJ/$$mol and the density of liquid ethanol is $$0.790 g/mL. $$How much energy (in kJ) is required to vaporize the sample?

Accepted Answer

12.9 kJ

Question 12

Which of the following statements about quantum mechanics experiments is incorrect?

Accepted Answer

The Heisenberg's Uncertainty Principle is about the measurements of the variables of an electron. This states that the position and velocity of an electron are never known.

Question 13

Identify the number of unpaired electrons present in the following elements: S, Co, Ca, Cl.

Accepted Answer

S: 2 unpaired $$e^-$$; Co: 3 unpaired $$e^-$$; Ca: 0 unpaired $$e^-$$; Cl: 1 unpaired $$e^-$$

Question 14

Which of the following processes is endothermic?

Accepted Answer

A only

Question 15

Determine the enthalpy of the reaction $$	ext{Ag}_2	ext{O} (s) + 2 	ext{HCl} (aq) ightarrow 2 	ext{AgCl} (s) + 	ext{H}_2 (g) + 	ext{O}_2 (g)$$ using Hess's law and the following data:

$$2 	ext{Ag} (s) + 1/2 	ext{O}_2 (g) ightarrow 	ext{Ag}_2	ext{O} (s)\ \Delta H = -31.1 kJ/$$mol
$$	ext{Ag} (s) + 1/2 	ext{Cl}_2 (g) ightarrow 	ext{AgCl} (s)\ \Delta H = -127.0 kJ/$$mol
$$	ext{H}_2	ext{O} (l) + 	ext{Cl}_2 (g) ightarrow 2 	ext{HCl} (aq) + 1/2 	ext{O}_2 (g)\ \Delta H = -48.6 kJ/$$mol
$$	ext{H}_2 (g) + 1/2 	ext{O}_2 (g) ightarrow 	ext{H}_2	ext{O} (l)\ \Delta H = -285.8 kJ/$$mol

Accepted Answer

-619.5 kJ/mol

Question 16

Consider two substances, M (5.16 g, $$18.6^\circC) $$and N (22.3 g, $$56.4^\circC$$), mixed to reach equilibrium at $$49.7^\circC. If $$the specific heat of N is $$2.34 J/g$\cdot$$°C, what is the specific heat of M?

Accepted Answer

8.16 J/g$$\cdot$$°C

Question 17

Which adjustment to Slater's rules would best account for the difference in electronic penetration of the nucleus for 3s, 3p, and 3d orbitals?

Accepted Answer

Assign a shielding value of s slightly smaller than that of p and a value for p smaller than that of d.

Question 18

Using the Born-Haber cycle and the provided data, determine $$\Delta H_f^\circ$$ for $$	ext{CuCl}_2(s)$$ and compare its stability to $$	ext{CuCl}(s)$$ ($$\Delta H_f^\circ = -137.2 kJ/$$mol). Data: $$	ext{Cu}(s) ightarrow 	ext{Cu}(g)\ \Delta H = 337.4 kJ/$$mol, $$	ext{IE}_1 = 745.5 kJ/$$mol, $$	ext{IE}_2 = 1957 kJ/$$mol, $$	ext{Cl}_2(g) ightarrow 2	ext{Cl}(g)\ 	ext{BDE} = 242.6 kJ/$$mol, $$	ext{EA} = -348.6 kJ/$$mol, $$	ext{LE} = -2824 kJ/$$mol.

Accepted Answer

$$\Delta H_f^\circ of$$ $$	ext{CuCl}_2(s) = -195.7 kJ/$$mol; $$	ext{CuCl}_2(s) is $$more stable.

Question 19

Calculate the change in energy for the following reactions based on the ionization energy and electron affinity of the involved elements:
(A) $$	ext{Li}(s) + 	ext{Cl}(g) ightarrow 	ext{Li}^+(g) + 	ext{Cl}^-(g)
(B$$) $$	ext{Li}(s) + 	ext{Cl}_2(g) ightarrow 	ext{Li}^+(g) + 	ext{Cl}^-(g)$$
Given: $$	ext{IE}_{	ext{Li}} = 520 kJ/$$mol, $$	ext{EA}_{	ext{Cl}} = -349 kJ/$$mol$$, 	ext{BDE}_{	ext{Cl}_2} = 242 kJ/$$mol.

Accepted Answer

(A) 171 kJ (B) 1191 kJ

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