Use these 3 free Unit 03 practice problems as your starting point. When you want more reps on particle counts, isotopes, ions, and atomic notation, premium unlocks Quick Sets of 3, Standard Sets of 9, and Extended Sets of 18 from this 174-problem bank.
3 Free Sample Problems
Work these 3 to find out whether particle counts and atomic symbols are becoming automatic — or whether you need more deliberate practice before they are.
#4Average Atomic Mass
Chlorine has two isotopes: Cl-35 (mass = 34.969 amu, abundance = 75.77%) and Cl-37 (mass = 36.966 amu, abundance = 24.23%). Calculate the average atomic mass of chlorine in amu.
#5Rutherford's Experiment
Rutherford's gold foil experiment showed that most alpha particles passed straight through the foil. What did this indicate about atomic structure?
#6Nuclear Symbol + Ion
Element X has the nuclear symbol 5626X and forms a 2+ ion. Which set of values — protons, neutrons, electrons — is correct for the ion?
Prep for the test — not just the homework
The 3 free problems show you where you stand. The full bank is how you close the gaps before the test.
Randomized every time — fresh problems that force real understanding, not answer memorization
Full worked solutions — see exactly where your setup went off track, not just whether you were right
174 problems across subatomic particles, isotopes, ions, and atomic notation
Quick (3), Standard (9), or Extended (18) — use whatever fits your schedule
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High School Chemistry · Unit 03 · Atomic Structure Practice