AP Exam Style Questions Unit 1

🔥 AP Chemistry Unit 1: Top 10 MCQs

1. What is the definition of a mole?

a) Mass of one atom of carbon-12 b) Number of particles in 12 grams of carbon-12 c) Volume of one gram of gas at STP d) Substance with Avogadro's number

2. What does mass spectroscopy measure?

a) Charge of an ion b) Mass-to-charge ratio of ions c) Energy of emitted photons d) Wavelength of absorbed light

3. How is the molar mass of a compound determined?

a) By counting the number of atoms b) By summing atomic masses c) By mass of one molecule d) By dividing mass by volume

4. What does the empirical formula represent?

a) Actual number of atoms b) Simplest whole-number ratio c) Mass % of each element d) Moles of each element

5. What is the molecular formula?

a) Simplest element ratio b) Total atom count c) Actual atom numbers d) Mass of a molecule

6. What is the purpose of photoelectron spectroscopy (PES)?

a) To find atomic radius b) To measure electron binding energies c) To calculate molecular polarity d) To find the number of neutrons

7. Which principle states that orbitals fill from lowest to highest energy?

a) Hund's Rule b) Pauli Exclusion Principle c) Aufbau Principle d) Heisenberg Uncertainty Principle

8. Why does ionic radius increase down a group?

a) More protons attract electrons b) Electrons are lost c) More electron shells added d) Electrons are closer to nucleus

9. Why does ionization energy decrease down a group?

a) More electron repulsion b) Electrons are closer to nucleus c) Outer electrons are farther away d) Smaller atomic radius

10. Why does electronegativity increase across a period?

a) Decreased nuclear charge b) More shielding effect c) Lower atomic mass d) Increased nuclear attraction