Structure One Practice Questions
SL Marks: /16
HL Marks: /20
(Updated Monthly)
11. The nuclear symbol of an ion is:
Br
Which of the following statements is correct?
A. It has 35 protons, 45 neutrons, and 36 electrons
B. It has 35 protons, 45 neutrons, and 34 electrons
C. It has 80 protons, 35 neutrons, and 36 electrons
D. It has 35 protons, 80 neutrons, and 36 electrons
A
-
80
35
13. Which of the following statements best reflects the principles of the quantum mechanical model of the atom?
A. Electrons orbit the nucleus in fixed circular paths called shells
B. Electrons are located at precise distances from the nucleus at all times
C. Electrons exist in orbitals where their position is based on a probability distribution
D. Electrons spiral inward toward the nucleus due to their negative charge
C
16. A mixture contains iodine crystals, salt (NaCl), sand, and ethanol. Which of the following correctly lists the most appropriate sequence of separation techniques to isolate all four components?
A. Filtration → Crystallization → Sublimation → Distillation
B. Filtration → Sublimation → Distillation → Crystallization
C. Sublimation → Filtration → Distillation → Crystallization
D. Filtration → Sublimation → Evaporation → Distillation
B
17. A student has 250 cm³ of a 6.00 mol/dm³ hydrochloric acid solution. They want to prepare 100 cm³ of 1.50 mol/dm³ HCl for a titration.
After removing the required volume of the concentrated acid and diluting it to 100 cm³, the student accidentally adds 10 cm³ too much distilled water.
What is the final concentration of the diluted HCl solution?
A. 1.25 mol/dm³
B. 1.35 mol/dm³
C. 1.40 mol/dm³
D. 1.50 mol/dm³
B
Higher Level
18. Why is low pressure maintained inside a mass spectrometer during the analysis process?
A. To keep the ions from colliding with air molecules during detection
B. To ensure that the sample remains in the vaporized state and does not condense
C. To allow ions to accelerate more easily in the electric field
D. To reduce the number of electrons needed for ionization
B
Higher Level
19. Which of the following best explains why the first ionization energy of sodium (Na) is significantly lower than that of magnesium (Mg)?
A. Sodium has fewer protons, so the nuclear charge is weaker
B. Sodium’s outer electron is closer to the nucleus and more tightly held
C. Magnesium has a larger atomic radius, so its electrons are harder to remove
D. Magnesium has more electron shielding, increasing repulsion and lowering IE
A
Higher Level
20. Why is the first ionization energy of oxygen lower than that of nitrogen, despite oxygen having a higher nuclear charge?
A. Oxygen’s valence electrons are farther from the nucleus than nitrogen’s
B. Oxygen has a paired electron in one of its 2p orbitals, creating greater electron repulsion
C. Nitrogen has more shielding from inner electrons than oxygen
D. Nitrogen’s orbitals are partially filled, making it easier to remove an electron
B
Higher Level