A student at Queen's College in Guyana was asked to calculate the number of neutrons in an atom of chlorine-35. The atomic number of chlorine is 17. How many neutrons does this atom contain?

Q: How do I try a free CXC Physics question?

Just tap any of the four options on this page — no signup, no card, nothing to install. You'll see the correct answer and a full mark-scheme-style explanation within a second. Each visit shows a fresh randomly-picked question from the live CXC CSEC Physics bank, so you can keep refreshing to try different ones before deciding whether to create a free account for daily access.

Q: Is Kramizo really free for CXC Physics students?

Yes — completely free. Every student gets 45 questions a day on the free plan, across any board and any subject, with no card required and no trial countdown. Kramizo's optional Pro plan removes the daily cap and adds analytics, but the free plan is genuinely free forever. We make money from the small percentage of students who choose to upgrade — not from selling data or ads.

Q: Are the Physics questions aligned to the CXC CSEC syllabus?

Every question is written against the published CXC CSEC Physics syllabus and reviewed for accuracy before being added to the bank. We match the command words (state, describe, explain, evaluate), mark allocations, and difficulty tier you'll see on real CXC past papers. Explanations are written in the style of official examiner mark schemes so students learn exactly what marks are being awarded for.

Question

A student at Queen's College in Guyana was asked to calculate the number of neutrons in an atom of chlorine-35. The atomic number of chlorine is 17. How many neutrons does this atom contain?

Accepted Answer

18 — Award 1 mark for correct calculation. Number of neutrons = mass number - atomic number = 35 - 17 = 18. A is incorrect as this is the number of protons. C is incorrect as this is the mass number. D is incorrect as this incorrectly adds the values.

Answer

18

Answer

35

Answer

17

Answer

52

One real Physics question.No signup. 30 seconds.

One real Physics question.
No signup. 30 seconds.