Q. What is the electronic configuration of the element with atomic number 12?
A.
[Ne] 3s2
B.
[He] 2s2 2p6
C.
[Ne] 3s1
D.
[Ar] 4s2
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Solution
The element with atomic number 12 is magnesium (Mg), and its electronic configuration is [Ne] 3s2.
Correct Answer: A — [Ne] 3s2
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Q. What is the electronic configuration of the element with atomic number 15?
A.
[Ne] 3s2 3p3
B.
[Ne] 3s2 3p4
C.
[Ne] 3s2 3p5
D.
[Ne] 3s2 3p2
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Solution
The element with atomic number 15 is phosphorus (P), and its electronic configuration is [Ne] 3s2 3p3.
Correct Answer: A — [Ne] 3s2 3p3
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Q. What is the electronic configuration of the element with atomic number 17?
A.
1s2 2s2 2p6 3s2 3p5
B.
1s2 2s2 2p6 3s2 3p4
C.
1s2 2s2 2p6 3s2 3p6
D.
1s2 2s2 2p6 3s2 3p3
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Solution
Chlorine (Cl) has the configuration 1s2 2s2 2p6 3s2 3p5.
Correct Answer: A — 1s2 2s2 2p6 3s2 3p5
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Q. What is the electronic configuration of the element with atomic number 20?
A.
[Ne] 3s2 3p6
B.
[Ar] 4s2
C.
[He] 2s2 2p6 3s2 3p6
D.
[Ne] 3s2 3p4
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Solution
The element with atomic number 20 is Calcium, which has the configuration [Ar] 4s2.
Correct Answer: B — [Ar] 4s2
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Q. What is the electronic configuration of the element with atomic number 26?
A.
[Ar] 4s2 3d6
B.
[Ar] 4s2 3d5
C.
[Kr] 5s2 4d6
D.
[Ar] 4s1 3d7
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Solution
The element with atomic number 26 is iron (Fe), and its electronic configuration is [Ar] 4s2 3d6.
Correct Answer: A — [Ar] 4s2 3d6
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Q. What is the electronic configuration of the element with atomic number 29?
A.
[Ar] 4s2 3d9
B.
[Ar] 4s2 3d10
C.
[Kr] 5s1 4d10
D.
[Ne] 3s2 3p6
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Solution
Copper (Cu) has the configuration [Ar] 4s2 3d9.
Correct Answer: A — [Ar] 4s2 3d9
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Q. What is the electronic configuration of the element with atomic number 30?
A.
[Ar] 4s2 3d8
B.
[Ar] 4s2 3d10
C.
[Ar] 4s2 3d6
D.
[Ar] 4s2 3d7
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Solution
The electronic configuration of Zinc (atomic number 30) is [Ar] 4s2 3d10.
Correct Answer: B — [Ar] 4s2 3d10
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Q. What is the electronic configuration of the element with atomic number 57?
A.
[Xe] 6s2
B.
[Xe] 4f1 5d1
C.
[Xe] 4f2
D.
[Xe] 5d2
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Solution
The electronic configuration of Lanthanum (atomic number 57) is [Xe] 6s2.
Correct Answer: C — [Xe] 4f2
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Q. What is the electronic configuration of the iron (Fe) atom?
A.
[Ar] 4s2 3d6
B.
[Ar] 4s2 3d5
C.
[Ar] 4s1 3d7
D.
[Ar] 4s2 3d4
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Solution
Iron (Fe) has 26 electrons, and its electronic configuration is [Ar] 4s2 3d6.
Correct Answer: A — [Ar] 4s2 3d6
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Q. What is the electronic configuration of the nitrogen atom?
A.
1s2 2s2 2p3
B.
1s2 2s2 2p4
C.
1s2 2s2 2p2
D.
1s2 2s2 2p5
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Solution
Nitrogen has 7 electrons, and its electronic configuration is 1s2 2s2 2p3.
Correct Answer: A — 1s2 2s2 2p3
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Q. What is the electronic configuration of the potassium ion (K+)?
A.
1s2 2s2 2p6 3s2
B.
1s2 2s2 2p6
C.
1s2 2s2 2p6 3s1
D.
1s2 2s2 2p6 3s2 3p1
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Solution
The potassium ion (K+) loses one electron, resulting in the configuration 1s2 2s2 2p6.
Correct Answer: B — 1s2 2s2 2p6
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Q. What is the electronic configuration of the sodium ion (Na+)?
A.
1s2 2s2 2p6
B.
1s2 2s2 2p5
C.
1s2 2s2 2p4
D.
1s2 2s2 2p3
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Solution
Sodium ion (Na+) has lost one electron, resulting in the configuration 1s2 2s2 2p6.
Correct Answer: A — 1s2 2s2 2p6
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Q. What is the empirical formula of a compound containing 40% carbon, 6.7% hydrogen, and 53.3% oxygen by mass?
A.
CH2O
B.
C2H4O2
C.
C3H6O3
D.
C4H8O4
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Solution
Convert percentages to grams (assume 100 g total): 40 g C, 6.7 g H, 53.3 g O. Convert to moles: C=3.33, H=6.67, O=3.33. The simplest ratio is 1:2:1, giving CH2O.
Correct Answer: A — CH2O
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Q. What is the empirical formula of a compound containing 40% carbon, 6.7% hydrogen, and 53.3% oxygen?
A.
CH2O
B.
C2H4O2
C.
C3H6O3
D.
C4H8O4
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Solution
Converting percentages to moles gives C: 40/12 = 3.33, H: 6.7/1 = 6.7, O: 53.3/16 = 3.33. The simplest ratio is 1:2:1, giving the empirical formula CH2O.
Correct Answer: A — CH2O
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Q. What is the empirical formula of C6H12O6?
A.
C2H4O2
B.
CH2O
C.
C3H6O3
D.
C6H12O6
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Solution
The empirical formula is the simplest whole number ratio, which is CH2O.
Correct Answer: B — CH2O
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Q. What is the empirical formula of glucose (C6H12O6)?
A.
C6H12O6
B.
CH2O
C.
C3H6O3
D.
C2H4O2
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Solution
The empirical formula is the simplest whole number ratio of the elements in a compound. For glucose, it is CH2O.
Correct Answer: B — CH2O
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Q. What is the energy band gap of silicon at room temperature?
A.
0.1 eV
B.
1.1 eV
C.
1.5 eV
D.
2.0 eV
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Solution
The energy band gap of silicon at room temperature is approximately 1.1 eV.
Correct Answer: B — 1.1 eV
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Q. What is the energy difference between the n=1 and n=2 levels in a hydrogen atom?
A.
10.2 eV
B.
13.6 eV
C.
1.89 eV
D.
3.4 eV
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Solution
The energy difference between n=1 and n=2 in hydrogen is 10.2 eV.
Correct Answer: A — 10.2 eV
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Q. What is the energy of a photon emitted during the transition from n=3 to n=2 in a hydrogen atom?
A.
10.2 eV
B.
1.89 eV
C.
12.1 eV
D.
3.4 eV
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Solution
The energy of the photon can be calculated using the Rydberg formula. The transition from n=3 to n=2 emits a photon of energy approximately 1.89 eV.
Correct Answer: B — 1.89 eV
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Q. What is the energy of a photon with a frequency of 5 x 10^14 Hz?
A.
3.1 x 10^-19 J
B.
2.5 x 10^-19 J
C.
4.0 x 10^-19 J
D.
6.6 x 10^-19 J
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Solution
The energy of a photon is given by E = hf. Using h = 6.63 x 10^-34 J.s, E = 6.63 x 10^-34 * 5 x 10^14 = 3.31 x 10^-19 J.
Correct Answer: A — 3.1 x 10^-19 J
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Q. What is the energy of a photon with a frequency of 5 x 10^14 Hz? (h = 6.63 x 10^-34 J.s)
A.
3.31 x 10^-19 J
B.
1.32 x 10^-19 J
C.
2.65 x 10^-19 J
D.
4.98 x 10^-19 J
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Solution
The energy of a photon is given by E = hν. Substituting the values gives E = 6.63 x 10^-34 J.s * 5 x 10^14 Hz = 3.31 x 10^-19 J.
Correct Answer: A — 3.31 x 10^-19 J
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Q. What is the energy of a photon with a frequency of 6 x 10^14 Hz?
A.
3.31 x 10^-19 J
B.
1.24 x 10^-19 J
C.
4.14 x 10^-19 J
D.
2.00 x 10^-19 J
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Solution
The energy of a photon is given by E = h * f, where h = 6.63 x 10^-34 J·s. Thus, E = 6.63 x 10^-34 * 6 x 10^14 = 4.14 x 10^-19 J.
Correct Answer: C — 4.14 x 10^-19 J
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Q. What is the energy of a photon with a wavelength of 500 nm?
A.
3.98 eV
B.
2.48 eV
C.
1.24 eV
D.
0.62 eV
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Solution
The energy of a photon is given by E = hc/λ. Using h = 6.626 x 10^-34 J·s and c = 3 x 10^8 m/s, E = (6.626 x 10^-34)(3 x 10^8)/(500 x 10^-9) = 3.98 eV.
Correct Answer: A — 3.98 eV
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Q. What is the energy of the ground state of a hydrogen atom?
A.
-13.6 eV
B.
-3.4 eV
C.
0 eV
D.
13.6 eV
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Solution
The energy of the ground state of a hydrogen atom is -13.6 eV.
Correct Answer: A — -13.6 eV
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Q. What is the energy stored in a capacitor of capacitance 10μF charged to a potential difference of 50V?
A.
0.0125 J
B.
0.025 J
C.
0.05 J
D.
0.1 J
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Solution
U = 1/2 * C * V² = 1/2 * (10 × 10^-6 F) * (50 V)² = 0.0125 J.
Correct Answer: B — 0.025 J
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Q. What is the energy stored in a capacitor of capacitance C charged to a voltage V?
A.
1/2 CV
B.
CV
C.
1/2 C/V
D.
C/V
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Solution
The energy (U) stored in a capacitor is given by the formula U = 1/2 CV².
Correct Answer: A — 1/2 CV
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Q. What is the energy stored in a capacitor with capacitance C charged to a voltage V?
A.
1/2 CV²
B.
CV
C.
1/2 V²/C
D.
C²V
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Solution
The energy (U) stored in a capacitor is given by the formula U = 1/2 CV².
Correct Answer: A — 1/2 CV²
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Q. What is the energy stored in a capacitor with capacitance C charged to voltage V?
A.
1/2 CV
B.
CV
C.
1/2 C/V
D.
C/V
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Solution
The energy (U) stored in a capacitor is given by the formula U = 1/2 CV².
Correct Answer: A — 1/2 CV
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Q. What is the enthalpy change for the formation of 1 mole of CO2 from its elements in their standard states?
A.
-393.5 kJ/mol
B.
-285.8 kJ/mol
C.
0 kJ/mol
D.
100 kJ/mol
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Solution
The standard enthalpy of formation of CO2 is -393.5 kJ/mol.
Correct Answer: A — -393.5 kJ/mol
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Q. What is the enthalpy change for the formation of water from hydrogen and oxygen?
A.
It is positive.
B.
It is negative.
C.
It is zero.
D.
It is undefined.
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Solution
The formation of water from hydrogen and oxygen is an exothermic reaction, resulting in a negative enthalpy change.
Correct Answer: B — It is negative.
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