AP Chemistry Unit 1 practice questions: Atomic Structure and Properties
8 original multiple-choice questions on AP Chem Unit 1, atomic structure and properties. Answer each one in your browser and read the explanation, then review the key ideas below.
Question 1 of 8
An element has two isotopes: 20% have a mass of 10 amu and 80% have a mass of 11 amu. What is its average atomic mass?
Question 2 of 8
Which atom has the highest first ionization energy?
Question 3 of 8
What is the ground-state electron configuration of iron (Fe, Z = 26)?
Question 4 of 8
Which atom has the largest atomic radius?
Question 5 of 8
How many moles are in 36 g of water? (molar mass 18 g/mol)
Question 6 of 8
How many valence electrons does a sulfur atom have?
Question 7 of 8
In a photoelectron spectrum, the peak with the highest binding energy comes from
Question 8 of 8
A compound is 40.0% carbon, 6.7% hydrogen and 53.3% oxygen by mass. What is its empirical formula?
Key ideas in Unit 1
- The mole links mass and number of particles: moles = mass ÷ molar mass, and 1 mol = 6.022 × 10²³ particles.
- Mass spectra show isotopes and their abundances; the average atomic mass is the weighted average.
- Electron configurations follow the Aufbau order. Photoelectron spectroscopy (PES) shows each sublevel as a peak, with core electrons at the highest binding energy.
- Periodic trends come from Coulomb's law: across a period, radius shrinks and ionization energy and electronegativity rise; down a group the opposite happens.
- Empirical formulas come from mass percentages: convert to moles and find the simplest whole-number ratio.
More AP Chem practice
Unit 2: Compound Structure and Properties →
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