Which of the following elements does not contain neutrons?
- AOxygen
- BNitrogen
- CHydrogen
- DCopper
- ENone of the above/More than one of the above
Show answer and explanation
Correct answer: (c) Hydrogen
Explanation
The commonest isotope of hydrogen, protium (¹H), has one proton and no neutron: it is the only common atom without one.
Hydrogen's other isotopes do have neutrons: deuterium (²H) has one and tritium (³H) has two. Oxygen, nitrogen and copper atoms all contain neutrons.